Food Science and Technology

This study was conducted to determine microbial contamination of mobile phones in the city of Dammam, in the eastern region of Saudi Arabia, and identify the most important microbial species associated with these phones in order to take the necessary remedial measures. Materials and Methods: The analysis of a total of 202 samples was done to identify fungal and pathogenic bacteria isolates. Sterile swabs were firmly passed on the handset, the buttons and the screens of mobile phones, then inoculated into media of bacteria and fungi. Frequency distribution of isolates were calculated. Results: There were 737 isolated of the following bacteria:

This work was undertaken to study the effect of Aspergillus infection on phenolic compounds in beans from four cultivars of the coffee plant (Coffea arabica L.). The effects of storage conditions of the coffee beans were also examined. Methodology and results: Beans from four varieties of coffee were artificially infected with three species of Aspergillus: A. niger, A. melleus and A. alliacus, and stored at 0, 8 and 25 ± 2 °C). After 3, 6 and 9 months, the contents of phenolic compounds in the beans were determined using high performance liquid chromatography (HPLC). Conclusion, significance and impact study: The results of this study showed that phenolic compounds were qualitatively and quantitatively higher in the inoculated beans as compared with the uninfected control beans, reflecting a possible induced defense mechanism in the infected beans. Increased storage periods resulted in higher levels of phenols, but the average total, bound and free phenols did not differ between the cultivars tested. Effective control of Apergillus infection in coffee beans can prevent such changes in phenolics that may affect their commercial value.

Contemporary lifestyles dictate that people spend between 60 and 90% of their daily lives indoors. For those living in warm climates, air conditioning is thus considered a necessity. Air conditioners function by removing hot and humid air from building interior and replacing it with cooler air. Microorganisms are considered among the most important sources of poor quality of indoor air, and contamination of this air by microbial pollutants is being increasingly recognized as a public health problem and a probable cause of the so-called sick building syndrome. In this regard, microfiber glass panel filters are considered to provide an effective solution for air filtration and have been demonstrated to improve air quality in many applications. However, recent research has demonstrated that certain microorganisms are able to colonize panel filter surfaces. Studies on selected microbes isolated from the most commonly used filters have revealed that the bacterial and fungal moist masses carried on sponge-type filters are greater than those carried on polyester and high-efficiency particulate air (HEPA) filters. Moreover, microbial moist mass has been found to increase with increasing incubation time. In addition, recent research has shown that certain microorganisms, particularly fungi, can colonize the materials used in heating, ventilation, and airconditioning systems (HVAC).

Background Extracellular production of fungal lipases especially the lipases obtained from the Aspergilli has gained immense interest in recent years due to its diverse biotechnological applications. In this study, we focused on determining the fermentation parameters required for the optimal lipase production. Methods A total of 256 fungal isolates were obtained from oil seeds. From each genus, one isolate was selected to evaluate lipase production using phenol red and tributyrin plate assays. Lipase activity was estimated using the spectrophotometric pNPP hydrolysis assay. The highest lipase producer isolates were identified using 18S ribosomal RNA gene sequencing. The genetic variability was determined by random amplified polymorphic DNA (RAPD) analysis and the dendrogram was constructed using the unweighted pair group method with arithmetic averages method. The isolates were examined in a submerged fermentation culture (Smf) to measure the effect of temperature, pH, incubation t...

Aspergillus niger MH078571.1 and A. niger MH079049.1 were identified previously as the two highest Aspergillus niger strains producing lipase. Biochemical characterizations of lipase activity and stability for these two strains were examined and revealed that the optimal temperature is 45 °C at pH 8for A. niger MH078571.1 and 55 °C for MH079049.1. The lipase production of both strains was studied on medium contains waste oil, as a cheap source to reduce the industrial cost, showed that the optimal incubation period for the enzyme production is 3 days. Moreover, an experiment on lipase activates in organic solvents demonstrated that 50% of acetone is the best solvent for the two strains. In the presence of surfactants, 0.1% of tween 80 surfactant showed the best lipase activities. Furthermore, Mg2+ and Zn2+ ions enhanced the lipase activity of A. niger MH078571.1, while Na2+ and Cu2+ enhanced the enzyme activity of A. niger MH079049.1. Lipase activity was also tested for industrial a...

Silver is an important industrial metal used in several areas such as photographic and x-ray films, jewelries, silver wares and electronic objects. Silver is used for photographic film/x-ray film because of its matchless quality as a light-sensitive material for making a photographic image. Silver is not destroyed in the photographic process and it can be reused and recovered. Results have proven that, bacterial alkaline protease can be used to extract silver in 30 min, but its activity decreases with increasing incubation period. Gelatin hydrolysis was monitored by measuring the increase in turbidity of the hydrolysate, which was accompanied by release of protein and hydroxyproline. The protease of the culture filtrate used was 97 U/ml after 30 min, but it decreased to 86.5U/ml after 60 min. After 90 min, it reached 85 U/ml. A great inactivation was recorded after 120 min; it got to 39.5 and 36.5% (U/ml) after 180 min. Gelatin layer was stripped completely within 30 min with 97 U m...

This Study Aimed to determine and identify fungi associated with four varieties of coffee beans (Coffea arabica L.) were collected from different grocery stores and retail markets in an eastern region of the Kingdom of Saudi Arabia: harary, lukkimy, habbashy and barry. However the highest percentage of fungal infection was associated with harary (36.26%of infection) followed by lukkimy (29.13%), habbashy (20.50%) and barry (14.12%). Several fungi associated with four varieties were isolated at the following frequencies: Aspergillus niger (74.71%), Aspergillus alliaceus (7.33%), Aspergillus melleus (4.32%), Aspergillus tubingensis (4.27%), Fusarium solani (3.56%), Aspergillus flavus (2.01%), Penicillium oxalicum (1.61%), Alternaria alternata (1.2%), Emericella nidulans (0.85%) and Paecilomyces variotii (0.15%). The potency of the first five most frequent fungi to infect all studied seeds was ranked, in decreasing order, as: A. niger, A. alliaceus and A.melleus (100%) however Fusarium...

The objective of this study was to investigate the effect of Rhizoctonia solani and Fusarium culmorum, which caused root rot, on the growth and yield of wheat and barley plants. Wheat cv. ‘Yecorarogo’ and barley cv. ‘Gustuo’ were planted in soil artificially infected with R. solani and F. culmorum. There was a significant decrease in the growth and yield of infected plants compared with healthy plants, in particular the length, fresh and dry weight of roots and shoots, and the number of grains for each spike. Both fungi damaged wheat plants more than barley plants. R. solani had the greatest effect on the growth and yield of wheat and barley. The content of biochemical compounds also decreased in all cases of infection. Total carbohydrate, proteins and fats decreased in the range between 23.28-45.68, 0.55-26.22 and 28.45-59.94%, respectively.

This study aimed to identify fungi associated with ten varieties of legumes seeds in an eastern region of the Kingdom of Saudi Arabia: Lupine (Lupinus albus L.), dry and kidney beans (Phaseolus vulgaris), cowpea and mung beans (Vigna radiata L.), faba and field beans (Vicia faba L.), brown and green lentil (Lens culinaris), chickpea (Cicer judaicum). The highest percentage of fungal infection was associated with mung bean (23.29% of infection) followed by faba beans (15.75%), field beans (13.87%), dry beans (11.99%), brown lentil (11.13%), lupine (6.69%), kidney beans (6.16%), green lentil (5.14%), cowpea (3.25%) and chickpea (2.74%). Several fungi associated with these were isolated at the following frequencies: Rhizoctonia solani (21.18%), Pythium aphanidermatum (17.8%), Sclerotinia sclerotiorum (13.04%), Alternaria alternata (12.18%), Aspergillus flavus (9.43%), Penicillium spp. (6.86%), Aschocayta spp. and Phytophthora spp. (4.12%). The potency of the first four most frequent fu...

Endophytic fungi serve as a reservoir for important secondary metabolites. The current study focused on the antibacterial properties of endophytic fungi isolated from Artemisia sieberi. Initially, six endophytic fungi were isolated and purified from the stem of A. sieberi. Endophytic fungi were identified by morphological characteristics, as well as by molecular identification using 18S rRNA gene sequencing method. All the six isolates were subjected to the preliminary screening for their antibacterial activity against nine important pathogenic bacteria using the disk-diffusion method. Crude extracts of the most active isolate were obtained using ethyl acetate. Antibacterial activity of the ethyl acetate extract was evaluated using well diffusion method on the selected isolate. The antibacterial efficiency of the selected isolate was evaluated by determining the Minimum Inhibitory Concentration (MIC). MIC values were in appreciable quantity against both Gram-positive and Gram-negati...