New data on biogas production and treatment of cattle wastewater were registered using an upflow ... more New data on biogas production and treatment of cattle wastewater were registered using an upflow anaerobic sludge blanket-anaerobic filter (UASB-AF) hybrid reactor under mesophilic temperature conditions (37 W C). The reactor was operated in semi-continuous mode with hydraulic retention times of 6, 5, 3 and 2 days and organic loading rates of 3.8, 4.6, 7.0 and 10.8 kg COD t m À3 d À1 . Biogas volumes of 0.6-0.8 m 3 m À3 d À1 (3.8-4.6 kg COD t m À3 d À1 ) and 1.2-1.4 m 3 m À3 d À1 (7.0-10.8 kg COD t m À3 d À1 ), with methane concentrations between 69 and 75%, were attained. The removal of organic matter with values of 60-81% (COD t ) and 51-75% (COD s ) allowed methane yields of 0.155-0.183 m 3 CH 4 kg À1 COD t and 0.401-0.513 m 3 CH 4 kg À1 COD s to be obtained. Volatile solids were removed in 34 to 69%, with corresponding methane yields of 0.27 to 0.42 m 3 CH 4 kg À1 VS removed . The good performance of the novel hybrid reactor was demonstrated by biogas outputs higher than reported previously in the literature, along with the quality of the gas obtained in the various experimental phases. The hybrid reactor investigated in this study presents comparative advantages, particularly in relation to conventional complete mixture units, considering economic factors such as energy consumption, reactor volume and installation area.
Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a w... more Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, most of the studies focusing on MELs high titre production have been relying in the use of vegetable oils with impact on the sustainability and process economy. Herein, we report for the first time MELs production using oils produced from microalgae. The bio-oil was extracted from Neochloris oleoabundans and evaluated for their use as sole carbon source or in a co-substrate strategy, using as an additional carbon source D-glucose, on Moesziomyces spp. cultures to support cell growth and induce the production of MELs. Both Moesziomyces antarcticus and M. aphidis were able to grow and produce MELs using algae-derived bio-oils as a carbon source. Using a medium containing as carbon sources 40 g/L of D-glucose and 20 g/L of bio-oils, Moesziomyces antarcticus and M. aphidis produced 12.47 ± 0.28 and 5.72 ± 2.32 g/L of MELs, respectively. Interesti...
In this work, primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) separatel... more In this work, primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) separately, or mixed at the ratios of 1:1 (PBWW:SBWW) and 1:7 (PBWW:SBWW), with or without supplementation with sugarcane molasses (SCM), were used as culture media for lipid production by a mixed culture of the oleaginous yeast Rhodosporidium toruloides NCYC 921 and the microalgae Tetradesmus obliquus (ACOI 204/07). Flow cytometry was used to understand the dynamics of the two micro-organisms during the mixed cultures evolution, as well as to evaluate the physiological states of each microorganism, in order to assess the impact of the different brewery effluent media composition on the microbial consortium performance. Both brewery wastewaters (primary and secondary) without supplementation did not allow R. toruloides heterotrophic growth. Nevertheless, all brewery wastewater media, with and without SCM supplementation, allowed the microalgae growth, although the yeast was the dominant population. The maximum total biomass concentration of 2.17 g L -1 was achieved in the PBWW mixed cultivation with 10 g L -1 of SCM. The maximum lipid content (14.86% (w/w DCW)) was obtained for the mixed culture developed on SBWW supplemented with 10 g L -1 of SCM. This work demonstrated the potential of using brewery wastewater supplemented with SCM as a low-cost culture medium to grow R. toruloides and T. obliquus in a mixed culture for brewery wastewater treatment with concomitant lipid production.
In this study, secondary brewery wastewater (SBWW) supplemented with sugarcane molasses (SCM) was... more In this study, secondary brewery wastewater (SBWW) supplemented with sugarcane molasses (SCM) was used for SBWW treatment with concomitant lipid and carotenoid production by the yeast Rhodosporidium toruloides NCYC 921. In order to improve the biomass production, ammonium sulfate, yeast extract and urea were tested as nitrogen sources. Urea was chosen as the best low-cost nitrogen source. A fed-batch cultivation was carried out with SBWW supplemented with 10 g L -1 of sugarcane molasses as carbon source, and 2 g L -1 of urea as nitrogen source. A maximum biomass concentration of 42.5 g L -1 was obtained at t = 126.5 h and the maximum biomass productivity was 0.55 g L -1 h -1 at t = 48.25 h. The maximum lipid content was 29.9 % w/w (DCW) at t = 94 h of cultivation and the maximum carotenoid content was 0.23 mg g -1 at 120 h of cultivation. Relatively to the SBWW treatment, after the batch phase, 45.8 % of total Kjeldahl nitrogen removal, 81.7 % of COD removal and 100 % of sugar consumption were observed. Flow cytometry analysis revealed that 27.27 % of the cells had injured membrane after the inoculation. This proportion was reduced to 10.37 % at the end of the cultivation, indicating that cells adapted to the growth conditions.
• An inexpensive strategy was used to valorize fish canning industry by products. • Urea complexa... more • An inexpensive strategy was used to valorize fish canning industry by products. • Urea complexation was more efficient than winterization. • The solid fraction contained 79.94% (w/w) of saturated and monounsaturated FAME. • The liquid fraction was further analysed by preparative HPLC analysis. • After HPLC analysis, an oil fraction containing 89.25% EPA (w/w) was obtained.
The Science of the total environment, Jan 20, 2018
Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical al... more Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical alveolar flat panel photobioreactors, operated in batch and continuous mode, after previous digestion in a hybrid anaerobic reactor. In batch operation, removal efficiencies ranges of 65 to 70% of COD, 98 to 99% of NH and 69 to 77.5% of PO after 12days were recorded. The corresponding figures for continuous flow were from 57 to 61% of COD, 94 to 96% of NH and 65 to 70% of PO with mean hidraulic retention time of 12days. Higher rates of CO fixation (327-547mgLd) and higher biomass volumetric productivity (213-358mgLd) were obtained in batch mode. This microalgae-mediated process can be considered promising for bioremediation and valorization of effluents produced by cattle breeding yielding a protein-rich microalgal biomass that could be eventually used as cattle feed.
Journal of Industrial Microbiology & Biotechnology, 2006
The potential use of n-dodecane as an oxygen vector for enhancement of Crypthecodinium cohnii gro... more The potential use of n-dodecane as an oxygen vector for enhancement of Crypthecodinium cohnii growth and docosahexaenoic acid (DHA) production was studied. The volumetric fraction of oxygen vector influenced the gas-liquid volumetric mass transfer coefficient k L a positively. The k L a increased almost linearly with the increase of volumetric fraction of n-dodecane up to 1%. The stirring rate showed a higher influence on the k L a than the aeration rate. The effects of this hydrocarbon on C. cohnii growth and DHA production were then investigated. A control batch fermentation without n-dodecane addition (CF) and a batch fermentation where n-dodecane 1% (v/v) was added (DF) were carried out simultaneously under the same experimental conditions. It was found that, before 86.7 h of fermentation, the biomass concentration, the specific growth rate, the DHA, and total fatty acids (TFA) production were higher in the CF. After this fermentation time, the biomass concentration, the DHA and TFA production were higher in the DF. The highest DHA content of biomass (6.14%), DHA percentage of TFA (51%), and DHA production volumetric rate r DHA (9.75 mg l À1 h À1) were obtained at the end of the fermentation with n-dodecane (135.2 h). The dissolved oxygen tension (DOT) was always higher in the DF, indicating a better oxygen transfer due to the oxygen vector presence. However, since the other C. cohnii unsaturated fatty acids percentages did not increase with the oxygen availability increase due to the n-dodecane presence, a desaturase oxygen-dependent mechanism involved in the C. cohnii DHA biosynthesis was not considered to explain the DHA production increase. A selective extraction through the n-dodecane was suggested. Keywords Crypthecodinium cohnii AE n-Dodecane AE k L a AE DHA production and CSTR Abbreviations CF: Control batch fermentation without n-dodecane AE CSTR: Continuous stirred tank reactor AE DF: Batch fermentation with n-dodecane 1% (v/v) AE DHA: Docosahexaenoic acid (22:6x3) AE DOT: Dissolved oxygen tension AE DPM: Dynamic pressure method AE k L a: Gas-liquid volumetric mass transfer coefficient (h À1) AE PUFA: Polyunsaturated fatty acids AE TAG: Triacylglycerols AE TFA: Total fatty acids AE r DHA : DHA production volumetric rate (g l À1 h À1) AE rpm: Rotations per minute AE r TFA : TFA production volumetric rate (g l À1 h À1) AE vvm: Volume of gas per volume of aerated liquid per minute
Chrypthecodinium cohnii lipids have been almost exclusively used as a source of Docosahexaenoic a... more Chrypthecodinium cohnii lipids have been almost exclusively used as a source of Docosahexaenoic acid (DHA). Such an approach wastes the remaining microalgal lipid fraction. The present work presents a novel process to produce C. cohnii biomass, using low-cost industrial by-products (raw glycerol and corn steep liquor), in a 7L-bioreactor, under fed-batch regime. At the end of the fermentation, the biomass concentration reached 9.2 g/L and the lipid content and lipid average productivity attained 28.0% (w/w dry cell weight) and 13.6 mg/L h, respectively. Afterwards the microalgal biomass underwent a saponification reaction to produce fatty acid (FA) soaps, which were further converted into FA ethyl ester (FA EE). C. cohnii FA EE mixture was then fractionated, using the urea complexation method at different temperatures, in order to obtain a polyunsaturated fatty acid ethyl ester (PUFA EE) rich fraction, that could be used for food/pharmaceutical/cosmetic purposes, and a saturated fatty acid ethyl ester (SAT EE) rich fraction, which could be used as biodiesel. The temperature that promoted the best separation between PUFA and SAT EE, was -18 • C, resulting in a liquid fraction with 91.6% (w/w) DHA, and a solid phase with 88.2% of SAT and monounsaturated fatty acid ethyl ester (MONOUNSAT), which could be used for biodiesel purposes after a hydrogenation step.
This study evaluated the production of endoxylanases by Streptomyces malaysiensis AMT-3 in submer... more This study evaluated the production of endoxylanases by Streptomyces malaysiensis AMT-3 in submerged fermentation using by-products of the food industry at 28ºC. In shake-flasks experiments, the highest endoxylanase activity of 45.8 U.mL-1 was observed within 6 days in a medium containing (w/v) 2.5% wheat bran and 1.2% corn steep liquor. The same culture conditions were used to evaluate the enzyme production in a 2 L stirred tank reactor under different agitation (300, 450 and 600 rev.min-1) and aeration (30 and 60 L.h-1) conditions. The use of 450 rev.min-1 coupled to an aeration of 90 L.h-1 resulted on 81.3 U.mL-1 endoxylanase activity within 5 days. The effect of temperature and pH on endoxylanase activity and stability showed the highest activity at 60 ºC and pH 6.0. Zymography showed the presence of three xylanolytic bands with molecular masses of 690, 180 and 142 kDa. The results showed that the thermotolerant actinobacterial endoxylanase can be produced in high titers using by-product of the food industry.
Microalgae represent a promising solution in addressing the impacts associated with the current a... more Microalgae represent a promising solution in addressing the impacts associated with the current agricultural and manufacturing practices which are causing irreparable environmental damage. Microalgae have considerable biosynthetic potential, being a rich source of lipids, proteins, and high-value compounds. Under the scope of the H2020-BBI MULTI-STR3AM project, an innovative large-scale production system of valuable commodities for the food, feed, and fragrance sectors is being developed on the basis of microalgae, reducing costs, increasing the scale of production, and boosting value chain sustainability. In this work, we aimed to create a process model that can mimic an industrial plant to estimate mass and energy balances, optimize scheduling, and calculate production costs for a large-scale plant. Three autotrophic microalgae strains (Nannochloropsis sp., Dunaliella sp. and Spirulina sp.) were considered for this assessment, as well as the use of locally sourced CO2 (flue gas). ...
CIES2020: As Energias Renováveis na Transição Energética: Livro de Comunicações do XVII Congresso... more CIES2020: As Energias Renováveis na Transição Energética: Livro de Comunicações do XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia Solar. Helder Gonçalves, Manuel Romero (Ed.). Lisboa, Portugal: LNEG, 3-5 Novembro, 2020, p. 671-675. ISBN: 978-989-675-076-3
Climate change caused by the excessive use of non-renewable resources as a means of supporting th... more Climate change caused by the excessive use of non-renewable resources as a means of supporting the current society demands is forcing the development of circular economy models and social, economic and environmental balanced solutions. In Portugal, in recent decades, important progresses have been made on waste resources management practices in line with the objectives and directives of the European Union. The urban and industrial wastes are, to a certain extent, a case of success since the effort developed has created tools for the prevention, control, recovery and recycling of a considerable percentage of the generated amounts. However, this effort has not yet reached its full potential, and there are still diverse underexplored issues, such as a systematic assessment of the waste biomass suitability for specific energy conversion technologies, and the promotion of non-food-competing energy crops on marginal lands. CONVERTE will identify and quantify the different waste biomass types generated in the Portuguese continental territory, and shall develop a biomass-driven energy matrix that correlates the biomass types with eight technological value chains for heat, power and/or advanced biofuels as main products. This is expected to impact positively on the national energy security and to reduce the overall Portuguese greenhouse gas (GHG) emissions, namely in the transport sector, contributing to increase the country sustainability score.
2016. Scoping the potencial for outdoor microalgae production in the Azores. Arquipelago. Life an... more 2016. Scoping the potencial for outdoor microalgae production in the Azores. Arquipelago. Life and Marine Sciences 33: 57-70. Microalgae cultivation has received much attention due to some desirable characteristics such as fast growth rates, high photosynthetic efficiencies and the production of valuable biochemicals. Mass cultivation of microalgae for commercial purposes is already a reality in some locations being an activity with approximately 45 years. The Azores archipelago, located in the North Atlantic Ocean off the coast of Portugal, features a temperate climate. To evaluate the feasibility of local outdoor microalgae production, certain fundamental factors must be analysed. In this study water, light, temperature, carbon sources, nutrients, international outlook and regional context were analyzed from the perspective of a local outdoor commercial microalgae production. A SWOT analysis was applied to the analysed factors to evaluate the strengths, weaknesses, opportunities a...
This study evaluates the application of biomass produced from the treatment of domestic sewage in... more This study evaluates the application of biomass produced from the treatment of domestic sewage in high-rate ponds (HRPs) as feedstock for the production of bio-oil via hydrothermal liquefaction (HTL). The effects of reaction time, temperature, and biomass/water ratio on the yield of bio-oil were assessed. In addition, a balance of carbon and nitrogen among the products (bio-oil, aqueous phase, solid residue, and gas) was carried out, in order to evaluate the quality of the bio-oil and possibilities for increasing value from the byproducts. In a 15-min operation at 300 C with biomass/water ratio of 1/10 (w.w À1), the bio-oil yield was of 44.4% (Dry Ash Free-daf-basis). Under every condition tested, the solid residue was the most abundant byproduct, mostly due to the high ash content in the biomass. The minimum nitrogen recovery in the bio-oil was 57%, obtained in the operation at 275 C, which is considered the main disadvantage of the process. The use of biomass directly after its production may result in an excessive consumption of energy due to the high water content. However, the need for drying is reduced when compared to other microalgal-based bioenergy production processes, potentially achieving a positive energy balance in the HTL.
Carob pulp syrup (CPS) was used as carbon source to produce carotenoids from Rhodosporidium torul... more Carob pulp syrup (CPS) was used as carbon source to produce carotenoids from Rhodosporidium toruloides. To increase the carbon concentration in the growth medium aiming at the carotenoid production improvement, the CPS was concentrated and two different total sugar (TS) concentrations (195.6 g/L and 548.7 g/L) were studied. CPS 195.6 g/L TS contained 4.1 g/L and 0.7 g/L of hydroxymethyl furfural (HMF) and furfural, respectively. CPS 548.7 g/L TS contained 17.7 g/L of HMF and 1.2 g/L of furfural, respectively. > 42% of metabolically active cells (with intact membrane and enzymatic activity) were detected throughout the course of the yeast cultivation on CPS 195.6 g/L TS. On the contrary, the proportion of metabolically active cells was always below 28% during the yeast cultivation on CPS 548.7 g/L TS. Nevertheless, the maximum carotenoid content and productivity (0.42 mg/g and 0.43 mg/Lh, respectively) were obtained when using CPS 548.7 g/L TS.
This study evaluated the operation of a hybrid anaerobic reactor fed with algal biomass cultivate... more This study evaluated the operation of a hybrid anaerobic reactor fed with algal biomass cultivated in effluent from the brewery industry. Three stages of operation were distinguished during the 72 days of semi-continuous functioning of the reactor: Stage 1 (S1), in which algal biomass was used as substrate; Stage 2 (S2), in which 10% (v/v) of the algal biomass was substituted by olive mill wastewater (OMW); and Stage 3 (S3), in which algal biomass was heat pre-treated. During S1, a loss of solids was observed, with an increment of organic matter in the outlet. The substitution of 10% of the volume of algal biomass by OMW tripled the methane productivity obtained in the previous stage by digestion of pure algal biomass. Heat pre-treatment was not efficient in rupturing the cell wall, and consequently did not have any effect on the increase in biogas production. The complementarity of substrates in the assessed conditions led to better results than the pre-treatment of the algal biomass.
CO 2 utilization in the production of biomass and biocompounds by three different microalgae The ... more CO 2 utilization in the production of biomass and biocompounds by three different microalgae The atmospheric CO 2 increase is considered the main cause of global warming. Microalgae are photosynthetic microorganisms that can help in CO 2 mitigation and at the same time produce value-added compounds. In this study, Scenedesmus obliquus, Chlorella vulgaris, and Chlorella protothecoides were cultivated under 0.035 (air), 5 and 10% (v/v) of CO 2 concentrations in air to evaluate the performance of the microalgae in terms of kinetic growth parameters, theoretical CO 2 biofixation rate, and biomass composition. Among the microalgae studied, S. obliquus presented the highest values of specific growth rate (μ = 1.28 d −1), maximum productivities (P max = 0.28 g L −1 d −1), and theoretical CO 2 biofixation rates (0.56 g L −1 d −1) at 10% CO 2. The highest oil content was found at 5% CO 2 , and the fatty acid profile was not influenced by the concentration of CO 2 in the inflow gas mixture and was in compliance with EN 14214, being suitable for biodiesel purposes. The impact of the CO 2 on S. obliquus cells' viability/cell membrane integrity evaluated by the in-line flow cytometry is quite innovative and fast, and revealed that 86.4% of the cells were damaged/permeabilized in cultures without the addition of CO 2 .
Green metrics is a methodology which allows the greenness of either new or already existing proce... more Green metrics is a methodology which allows the greenness of either new or already existing processes to be assessed. This paper is a part of a special issue devoted to green metrics in which this methodology is applied to different processes to assess bio and petrochemical routes. In this work, green metrics were used as a tool to validate and compare the petrochemical and biological processes of isoprene production. The Sumitomo process has been selected for this comparison as it is beneficial because of it using less expensive C 1 components as well as the fact that it has lower investment costs for a single-step process. The production of isoprene through a modified Escherichia coli bacterial process has been selected for comparison with the fossil pathway. The green metrics evaluation was performed for both processes to produce isoprene and to target 50,000 tonnes of isoprene yearly. Although, the calculated costs for the bio-isoprene are slightly higher than the actual market price of its fossil counterpart, the results obtained reveal that the bacteria-based isoprene production is able to substitute the petrochemical process, with material and energy efficiency. This conclusion has also been proved by the increasing number of industrial interest in bioisoprene. The challenge comes from the land use needed for the production of a carbon source which might be solved by the use of waste and residues which are rich in carbohydrates or lignocellulosic biomass which can be converted to simple sugars.
Background: Bacterium-bacterium antagonistic interactions could be important in the ecology of ma... more Background: Bacterium-bacterium antagonistic interactions could be important in the ecology of marine bacteria. Antimicrobial properties of microorganisms are exploited in various fields of human activities. Objectives: Antagonism of heterotrophic bacteria from different marine environments of tropical and temperate zones was examined. Materials and Methods: Bacteria were isolated from biofilm samples, tissues of hydrobionts and sea water. Isolates were characterized by phenotypic and 16S rRNA phylogenetic analyses. Agar diffusion assay was applied to investigate inhibitory interactions. 5 type strains and 21 strains of marine origin were used as test cultures. Results: 68.97% of isolates from temperate zone and 56.76% of tropical zone showed antimicrobial activity. The most active strains belonged to genera Pseudomonas and Pseudoalteromonas. Conclusions: Bacterial interspecies growth inhibition is widely distributed in marine environments. Marine bacteria, especially Vibrio spp., may be good probiotics which are active against pathogenic bacteria.
Journal of Industrial Microbiology and Biotechnology, 2013
Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and g... more Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and granularity in Rhodotorula glutinis mutant 400A15 grown under different oxygen transfer coefficients (k L a) and carbon to nitrogen ratios (C/N). A Doehlert distribution was used in order to select the best conditions that induced the highest carotenoids production. The highest β-carotene content (0.79 mg g−1 DCW) at the lowest k L a and C/N (5 × 10−3 s−1 and 11.3 respectively). Under these conditions, the biomass concentration attained 18.60 g L−1. The highest ratio of cells with permeabilised membranes (2.6 %), and the highest cell size and granularity were also obtained under these conditions. It was observed that C/N showed a stronger influence than the k L a on the measured cell parameters.
New data on biogas production and treatment of cattle wastewater were registered using an upflow ... more New data on biogas production and treatment of cattle wastewater were registered using an upflow anaerobic sludge blanket-anaerobic filter (UASB-AF) hybrid reactor under mesophilic temperature conditions (37 W C). The reactor was operated in semi-continuous mode with hydraulic retention times of 6, 5, 3 and 2 days and organic loading rates of 3.8, 4.6, 7.0 and 10.8 kg COD t m À3 d À1 . Biogas volumes of 0.6-0.8 m 3 m À3 d À1 (3.8-4.6 kg COD t m À3 d À1 ) and 1.2-1.4 m 3 m À3 d À1 (7.0-10.8 kg COD t m À3 d À1 ), with methane concentrations between 69 and 75%, were attained. The removal of organic matter with values of 60-81% (COD t ) and 51-75% (COD s ) allowed methane yields of 0.155-0.183 m 3 CH 4 kg À1 COD t and 0.401-0.513 m 3 CH 4 kg À1 COD s to be obtained. Volatile solids were removed in 34 to 69%, with corresponding methane yields of 0.27 to 0.42 m 3 CH 4 kg À1 VS removed . The good performance of the novel hybrid reactor was demonstrated by biogas outputs higher than reported previously in the literature, along with the quality of the gas obtained in the various experimental phases. The hybrid reactor investigated in this study presents comparative advantages, particularly in relation to conventional complete mixture units, considering economic factors such as energy consumption, reactor volume and installation area.
Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a w... more Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, most of the studies focusing on MELs high titre production have been relying in the use of vegetable oils with impact on the sustainability and process economy. Herein, we report for the first time MELs production using oils produced from microalgae. The bio-oil was extracted from Neochloris oleoabundans and evaluated for their use as sole carbon source or in a co-substrate strategy, using as an additional carbon source D-glucose, on Moesziomyces spp. cultures to support cell growth and induce the production of MELs. Both Moesziomyces antarcticus and M. aphidis were able to grow and produce MELs using algae-derived bio-oils as a carbon source. Using a medium containing as carbon sources 40 g/L of D-glucose and 20 g/L of bio-oils, Moesziomyces antarcticus and M. aphidis produced 12.47 ± 0.28 and 5.72 ± 2.32 g/L of MELs, respectively. Interesti...
In this work, primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) separatel... more In this work, primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) separately, or mixed at the ratios of 1:1 (PBWW:SBWW) and 1:7 (PBWW:SBWW), with or without supplementation with sugarcane molasses (SCM), were used as culture media for lipid production by a mixed culture of the oleaginous yeast Rhodosporidium toruloides NCYC 921 and the microalgae Tetradesmus obliquus (ACOI 204/07). Flow cytometry was used to understand the dynamics of the two micro-organisms during the mixed cultures evolution, as well as to evaluate the physiological states of each microorganism, in order to assess the impact of the different brewery effluent media composition on the microbial consortium performance. Both brewery wastewaters (primary and secondary) without supplementation did not allow R. toruloides heterotrophic growth. Nevertheless, all brewery wastewater media, with and without SCM supplementation, allowed the microalgae growth, although the yeast was the dominant population. The maximum total biomass concentration of 2.17 g L -1 was achieved in the PBWW mixed cultivation with 10 g L -1 of SCM. The maximum lipid content (14.86% (w/w DCW)) was obtained for the mixed culture developed on SBWW supplemented with 10 g L -1 of SCM. This work demonstrated the potential of using brewery wastewater supplemented with SCM as a low-cost culture medium to grow R. toruloides and T. obliquus in a mixed culture for brewery wastewater treatment with concomitant lipid production.
In this study, secondary brewery wastewater (SBWW) supplemented with sugarcane molasses (SCM) was... more In this study, secondary brewery wastewater (SBWW) supplemented with sugarcane molasses (SCM) was used for SBWW treatment with concomitant lipid and carotenoid production by the yeast Rhodosporidium toruloides NCYC 921. In order to improve the biomass production, ammonium sulfate, yeast extract and urea were tested as nitrogen sources. Urea was chosen as the best low-cost nitrogen source. A fed-batch cultivation was carried out with SBWW supplemented with 10 g L -1 of sugarcane molasses as carbon source, and 2 g L -1 of urea as nitrogen source. A maximum biomass concentration of 42.5 g L -1 was obtained at t = 126.5 h and the maximum biomass productivity was 0.55 g L -1 h -1 at t = 48.25 h. The maximum lipid content was 29.9 % w/w (DCW) at t = 94 h of cultivation and the maximum carotenoid content was 0.23 mg g -1 at 120 h of cultivation. Relatively to the SBWW treatment, after the batch phase, 45.8 % of total Kjeldahl nitrogen removal, 81.7 % of COD removal and 100 % of sugar consumption were observed. Flow cytometry analysis revealed that 27.27 % of the cells had injured membrane after the inoculation. This proportion was reduced to 10.37 % at the end of the cultivation, indicating that cells adapted to the growth conditions.
• An inexpensive strategy was used to valorize fish canning industry by products. • Urea complexa... more • An inexpensive strategy was used to valorize fish canning industry by products. • Urea complexation was more efficient than winterization. • The solid fraction contained 79.94% (w/w) of saturated and monounsaturated FAME. • The liquid fraction was further analysed by preparative HPLC analysis. • After HPLC analysis, an oil fraction containing 89.25% EPA (w/w) was obtained.
The Science of the total environment, Jan 20, 2018
Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical al... more Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical alveolar flat panel photobioreactors, operated in batch and continuous mode, after previous digestion in a hybrid anaerobic reactor. In batch operation, removal efficiencies ranges of 65 to 70% of COD, 98 to 99% of NH and 69 to 77.5% of PO after 12days were recorded. The corresponding figures for continuous flow were from 57 to 61% of COD, 94 to 96% of NH and 65 to 70% of PO with mean hidraulic retention time of 12days. Higher rates of CO fixation (327-547mgLd) and higher biomass volumetric productivity (213-358mgLd) were obtained in batch mode. This microalgae-mediated process can be considered promising for bioremediation and valorization of effluents produced by cattle breeding yielding a protein-rich microalgal biomass that could be eventually used as cattle feed.
Journal of Industrial Microbiology & Biotechnology, 2006
The potential use of n-dodecane as an oxygen vector for enhancement of Crypthecodinium cohnii gro... more The potential use of n-dodecane as an oxygen vector for enhancement of Crypthecodinium cohnii growth and docosahexaenoic acid (DHA) production was studied. The volumetric fraction of oxygen vector influenced the gas-liquid volumetric mass transfer coefficient k L a positively. The k L a increased almost linearly with the increase of volumetric fraction of n-dodecane up to 1%. The stirring rate showed a higher influence on the k L a than the aeration rate. The effects of this hydrocarbon on C. cohnii growth and DHA production were then investigated. A control batch fermentation without n-dodecane addition (CF) and a batch fermentation where n-dodecane 1% (v/v) was added (DF) were carried out simultaneously under the same experimental conditions. It was found that, before 86.7 h of fermentation, the biomass concentration, the specific growth rate, the DHA, and total fatty acids (TFA) production were higher in the CF. After this fermentation time, the biomass concentration, the DHA and TFA production were higher in the DF. The highest DHA content of biomass (6.14%), DHA percentage of TFA (51%), and DHA production volumetric rate r DHA (9.75 mg l À1 h À1) were obtained at the end of the fermentation with n-dodecane (135.2 h). The dissolved oxygen tension (DOT) was always higher in the DF, indicating a better oxygen transfer due to the oxygen vector presence. However, since the other C. cohnii unsaturated fatty acids percentages did not increase with the oxygen availability increase due to the n-dodecane presence, a desaturase oxygen-dependent mechanism involved in the C. cohnii DHA biosynthesis was not considered to explain the DHA production increase. A selective extraction through the n-dodecane was suggested. Keywords Crypthecodinium cohnii AE n-Dodecane AE k L a AE DHA production and CSTR Abbreviations CF: Control batch fermentation without n-dodecane AE CSTR: Continuous stirred tank reactor AE DF: Batch fermentation with n-dodecane 1% (v/v) AE DHA: Docosahexaenoic acid (22:6x3) AE DOT: Dissolved oxygen tension AE DPM: Dynamic pressure method AE k L a: Gas-liquid volumetric mass transfer coefficient (h À1) AE PUFA: Polyunsaturated fatty acids AE TAG: Triacylglycerols AE TFA: Total fatty acids AE r DHA : DHA production volumetric rate (g l À1 h À1) AE rpm: Rotations per minute AE r TFA : TFA production volumetric rate (g l À1 h À1) AE vvm: Volume of gas per volume of aerated liquid per minute
Chrypthecodinium cohnii lipids have been almost exclusively used as a source of Docosahexaenoic a... more Chrypthecodinium cohnii lipids have been almost exclusively used as a source of Docosahexaenoic acid (DHA). Such an approach wastes the remaining microalgal lipid fraction. The present work presents a novel process to produce C. cohnii biomass, using low-cost industrial by-products (raw glycerol and corn steep liquor), in a 7L-bioreactor, under fed-batch regime. At the end of the fermentation, the biomass concentration reached 9.2 g/L and the lipid content and lipid average productivity attained 28.0% (w/w dry cell weight) and 13.6 mg/L h, respectively. Afterwards the microalgal biomass underwent a saponification reaction to produce fatty acid (FA) soaps, which were further converted into FA ethyl ester (FA EE). C. cohnii FA EE mixture was then fractionated, using the urea complexation method at different temperatures, in order to obtain a polyunsaturated fatty acid ethyl ester (PUFA EE) rich fraction, that could be used for food/pharmaceutical/cosmetic purposes, and a saturated fatty acid ethyl ester (SAT EE) rich fraction, which could be used as biodiesel. The temperature that promoted the best separation between PUFA and SAT EE, was -18 • C, resulting in a liquid fraction with 91.6% (w/w) DHA, and a solid phase with 88.2% of SAT and monounsaturated fatty acid ethyl ester (MONOUNSAT), which could be used for biodiesel purposes after a hydrogenation step.
This study evaluated the production of endoxylanases by Streptomyces malaysiensis AMT-3 in submer... more This study evaluated the production of endoxylanases by Streptomyces malaysiensis AMT-3 in submerged fermentation using by-products of the food industry at 28ºC. In shake-flasks experiments, the highest endoxylanase activity of 45.8 U.mL-1 was observed within 6 days in a medium containing (w/v) 2.5% wheat bran and 1.2% corn steep liquor. The same culture conditions were used to evaluate the enzyme production in a 2 L stirred tank reactor under different agitation (300, 450 and 600 rev.min-1) and aeration (30 and 60 L.h-1) conditions. The use of 450 rev.min-1 coupled to an aeration of 90 L.h-1 resulted on 81.3 U.mL-1 endoxylanase activity within 5 days. The effect of temperature and pH on endoxylanase activity and stability showed the highest activity at 60 ºC and pH 6.0. Zymography showed the presence of three xylanolytic bands with molecular masses of 690, 180 and 142 kDa. The results showed that the thermotolerant actinobacterial endoxylanase can be produced in high titers using by-product of the food industry.
Microalgae represent a promising solution in addressing the impacts associated with the current a... more Microalgae represent a promising solution in addressing the impacts associated with the current agricultural and manufacturing practices which are causing irreparable environmental damage. Microalgae have considerable biosynthetic potential, being a rich source of lipids, proteins, and high-value compounds. Under the scope of the H2020-BBI MULTI-STR3AM project, an innovative large-scale production system of valuable commodities for the food, feed, and fragrance sectors is being developed on the basis of microalgae, reducing costs, increasing the scale of production, and boosting value chain sustainability. In this work, we aimed to create a process model that can mimic an industrial plant to estimate mass and energy balances, optimize scheduling, and calculate production costs for a large-scale plant. Three autotrophic microalgae strains (Nannochloropsis sp., Dunaliella sp. and Spirulina sp.) were considered for this assessment, as well as the use of locally sourced CO2 (flue gas). ...
CIES2020: As Energias Renováveis na Transição Energética: Livro de Comunicações do XVII Congresso... more CIES2020: As Energias Renováveis na Transição Energética: Livro de Comunicações do XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia Solar. Helder Gonçalves, Manuel Romero (Ed.). Lisboa, Portugal: LNEG, 3-5 Novembro, 2020, p. 671-675. ISBN: 978-989-675-076-3
Climate change caused by the excessive use of non-renewable resources as a means of supporting th... more Climate change caused by the excessive use of non-renewable resources as a means of supporting the current society demands is forcing the development of circular economy models and social, economic and environmental balanced solutions. In Portugal, in recent decades, important progresses have been made on waste resources management practices in line with the objectives and directives of the European Union. The urban and industrial wastes are, to a certain extent, a case of success since the effort developed has created tools for the prevention, control, recovery and recycling of a considerable percentage of the generated amounts. However, this effort has not yet reached its full potential, and there are still diverse underexplored issues, such as a systematic assessment of the waste biomass suitability for specific energy conversion technologies, and the promotion of non-food-competing energy crops on marginal lands. CONVERTE will identify and quantify the different waste biomass types generated in the Portuguese continental territory, and shall develop a biomass-driven energy matrix that correlates the biomass types with eight technological value chains for heat, power and/or advanced biofuels as main products. This is expected to impact positively on the national energy security and to reduce the overall Portuguese greenhouse gas (GHG) emissions, namely in the transport sector, contributing to increase the country sustainability score.
2016. Scoping the potencial for outdoor microalgae production in the Azores. Arquipelago. Life an... more 2016. Scoping the potencial for outdoor microalgae production in the Azores. Arquipelago. Life and Marine Sciences 33: 57-70. Microalgae cultivation has received much attention due to some desirable characteristics such as fast growth rates, high photosynthetic efficiencies and the production of valuable biochemicals. Mass cultivation of microalgae for commercial purposes is already a reality in some locations being an activity with approximately 45 years. The Azores archipelago, located in the North Atlantic Ocean off the coast of Portugal, features a temperate climate. To evaluate the feasibility of local outdoor microalgae production, certain fundamental factors must be analysed. In this study water, light, temperature, carbon sources, nutrients, international outlook and regional context were analyzed from the perspective of a local outdoor commercial microalgae production. A SWOT analysis was applied to the analysed factors to evaluate the strengths, weaknesses, opportunities a...
This study evaluates the application of biomass produced from the treatment of domestic sewage in... more This study evaluates the application of biomass produced from the treatment of domestic sewage in high-rate ponds (HRPs) as feedstock for the production of bio-oil via hydrothermal liquefaction (HTL). The effects of reaction time, temperature, and biomass/water ratio on the yield of bio-oil were assessed. In addition, a balance of carbon and nitrogen among the products (bio-oil, aqueous phase, solid residue, and gas) was carried out, in order to evaluate the quality of the bio-oil and possibilities for increasing value from the byproducts. In a 15-min operation at 300 C with biomass/water ratio of 1/10 (w.w À1), the bio-oil yield was of 44.4% (Dry Ash Free-daf-basis). Under every condition tested, the solid residue was the most abundant byproduct, mostly due to the high ash content in the biomass. The minimum nitrogen recovery in the bio-oil was 57%, obtained in the operation at 275 C, which is considered the main disadvantage of the process. The use of biomass directly after its production may result in an excessive consumption of energy due to the high water content. However, the need for drying is reduced when compared to other microalgal-based bioenergy production processes, potentially achieving a positive energy balance in the HTL.
Carob pulp syrup (CPS) was used as carbon source to produce carotenoids from Rhodosporidium torul... more Carob pulp syrup (CPS) was used as carbon source to produce carotenoids from Rhodosporidium toruloides. To increase the carbon concentration in the growth medium aiming at the carotenoid production improvement, the CPS was concentrated and two different total sugar (TS) concentrations (195.6 g/L and 548.7 g/L) were studied. CPS 195.6 g/L TS contained 4.1 g/L and 0.7 g/L of hydroxymethyl furfural (HMF) and furfural, respectively. CPS 548.7 g/L TS contained 17.7 g/L of HMF and 1.2 g/L of furfural, respectively. > 42% of metabolically active cells (with intact membrane and enzymatic activity) were detected throughout the course of the yeast cultivation on CPS 195.6 g/L TS. On the contrary, the proportion of metabolically active cells was always below 28% during the yeast cultivation on CPS 548.7 g/L TS. Nevertheless, the maximum carotenoid content and productivity (0.42 mg/g and 0.43 mg/Lh, respectively) were obtained when using CPS 548.7 g/L TS.
This study evaluated the operation of a hybrid anaerobic reactor fed with algal biomass cultivate... more This study evaluated the operation of a hybrid anaerobic reactor fed with algal biomass cultivated in effluent from the brewery industry. Three stages of operation were distinguished during the 72 days of semi-continuous functioning of the reactor: Stage 1 (S1), in which algal biomass was used as substrate; Stage 2 (S2), in which 10% (v/v) of the algal biomass was substituted by olive mill wastewater (OMW); and Stage 3 (S3), in which algal biomass was heat pre-treated. During S1, a loss of solids was observed, with an increment of organic matter in the outlet. The substitution of 10% of the volume of algal biomass by OMW tripled the methane productivity obtained in the previous stage by digestion of pure algal biomass. Heat pre-treatment was not efficient in rupturing the cell wall, and consequently did not have any effect on the increase in biogas production. The complementarity of substrates in the assessed conditions led to better results than the pre-treatment of the algal biomass.
CO 2 utilization in the production of biomass and biocompounds by three different microalgae The ... more CO 2 utilization in the production of biomass and biocompounds by three different microalgae The atmospheric CO 2 increase is considered the main cause of global warming. Microalgae are photosynthetic microorganisms that can help in CO 2 mitigation and at the same time produce value-added compounds. In this study, Scenedesmus obliquus, Chlorella vulgaris, and Chlorella protothecoides were cultivated under 0.035 (air), 5 and 10% (v/v) of CO 2 concentrations in air to evaluate the performance of the microalgae in terms of kinetic growth parameters, theoretical CO 2 biofixation rate, and biomass composition. Among the microalgae studied, S. obliquus presented the highest values of specific growth rate (μ = 1.28 d −1), maximum productivities (P max = 0.28 g L −1 d −1), and theoretical CO 2 biofixation rates (0.56 g L −1 d −1) at 10% CO 2. The highest oil content was found at 5% CO 2 , and the fatty acid profile was not influenced by the concentration of CO 2 in the inflow gas mixture and was in compliance with EN 14214, being suitable for biodiesel purposes. The impact of the CO 2 on S. obliquus cells' viability/cell membrane integrity evaluated by the in-line flow cytometry is quite innovative and fast, and revealed that 86.4% of the cells were damaged/permeabilized in cultures without the addition of CO 2 .
Green metrics is a methodology which allows the greenness of either new or already existing proce... more Green metrics is a methodology which allows the greenness of either new or already existing processes to be assessed. This paper is a part of a special issue devoted to green metrics in which this methodology is applied to different processes to assess bio and petrochemical routes. In this work, green metrics were used as a tool to validate and compare the petrochemical and biological processes of isoprene production. The Sumitomo process has been selected for this comparison as it is beneficial because of it using less expensive C 1 components as well as the fact that it has lower investment costs for a single-step process. The production of isoprene through a modified Escherichia coli bacterial process has been selected for comparison with the fossil pathway. The green metrics evaluation was performed for both processes to produce isoprene and to target 50,000 tonnes of isoprene yearly. Although, the calculated costs for the bio-isoprene are slightly higher than the actual market price of its fossil counterpart, the results obtained reveal that the bacteria-based isoprene production is able to substitute the petrochemical process, with material and energy efficiency. This conclusion has also been proved by the increasing number of industrial interest in bioisoprene. The challenge comes from the land use needed for the production of a carbon source which might be solved by the use of waste and residues which are rich in carbohydrates or lignocellulosic biomass which can be converted to simple sugars.
Background: Bacterium-bacterium antagonistic interactions could be important in the ecology of ma... more Background: Bacterium-bacterium antagonistic interactions could be important in the ecology of marine bacteria. Antimicrobial properties of microorganisms are exploited in various fields of human activities. Objectives: Antagonism of heterotrophic bacteria from different marine environments of tropical and temperate zones was examined. Materials and Methods: Bacteria were isolated from biofilm samples, tissues of hydrobionts and sea water. Isolates were characterized by phenotypic and 16S rRNA phylogenetic analyses. Agar diffusion assay was applied to investigate inhibitory interactions. 5 type strains and 21 strains of marine origin were used as test cultures. Results: 68.97% of isolates from temperate zone and 56.76% of tropical zone showed antimicrobial activity. The most active strains belonged to genera Pseudomonas and Pseudoalteromonas. Conclusions: Bacterial interspecies growth inhibition is widely distributed in marine environments. Marine bacteria, especially Vibrio spp., may be good probiotics which are active against pathogenic bacteria.
Journal of Industrial Microbiology and Biotechnology, 2013
Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and g... more Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and granularity in Rhodotorula glutinis mutant 400A15 grown under different oxygen transfer coefficients (k L a) and carbon to nitrogen ratios (C/N). A Doehlert distribution was used in order to select the best conditions that induced the highest carotenoids production. The highest β-carotene content (0.79 mg g−1 DCW) at the lowest k L a and C/N (5 × 10−3 s−1 and 11.3 respectively). Under these conditions, the biomass concentration attained 18.60 g L−1. The highest ratio of cells with permeabilised membranes (2.6 %), and the highest cell size and granularity were also obtained under these conditions. It was observed that C/N showed a stronger influence than the k L a on the measured cell parameters.
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