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Numerous studies have examined the feasibility of using microalgae as a long-term source of biofuel. This helped us to determine how different amounts of phosphorus changed the growth of lipids in Scenedesmus subspicatus, a freshwater microalga. This study examined the effects of various phosphorus concentrations on the biochemical makeup of algae, particularly the production of proteins and carbohydrates. When there was insufficient phosphorus, the investigation observed a significant increase in lipids and productivity of S. subspicatus. Additionally, gas chromatography was used to examine the fatty acid profiles of the green algae thoroughly. When Scenedesmus species were tested at different cell densities, the highest amount of chlorophyll was found to be 0.89 mg/L. The amounts of fatty acids in algae grown with 0.4 and 0.04 P of phosphorus were strongly correlated, as shown by the Pearson linear correlation coefficients. Gas chromatography analysis revealed that the major saturated fatty acids were stearic acid (C18:0) and palmitic acid (C16:0). In addition, confirming the presence of several unsaturated fatty acids (C16:3, C18:1, C18:2, and C18:3) has helped us learn more about S. subspicatus's complex lipid profile of S. subspicatus and how well it can be used to produce biofuels. [ABSTRACT FROM AUTHOR]

Objectives: The current study aimed to investigate the impact of different nutritional factors and growth conditions on biosurfactant production by bacterial isolates (EMB16 and EMB21) isolated from oil-contaminated soil samples. Methods: Based on the used quantitative and qualitative screening method in current study, the selected bacterial isolates showed a high potential to produce biosurfactant. Results: By using 16S rRNA sequence analysis, the bacterial isolates EMB16 and EMB21 were found to be closely related to Pseudomonas mendocina and Pseudomonas oleovorans, respectively. The ultimate yields of biosurfactant (8.06 ± 0.06 mg/ml) by Ps. mendocina EMB16 was with corn oil as a carbon source, urea as a nitrogen source, C/N ratio of 30, pH value of 7, and 2% inoculum size. For Ps. oleovorans EMB21, the maximum biosurfactant production (4.68 ± 0.14 mg/ml) was achieved by diesel oil as a carbon source, urea as a nitrogen source, C/N ratio of 30, pH of 7, and 5% size of inoculum. The best incubation period and temperature for the examined strains was 168 hrs. at 37°C. Conclusion: The results proved that Ps. mendocina EMB16 was the most efficient biosurfactant producer as it showed the greatest amount of biosurfactant concentration and lowest value of surface tension measurement with an emulsification index of 67 ± 6%. [ABSTRACT FROM AUTHOR]

This study aimed to characterize an efficient tannin-degrading microorganism through tannase production. Ten fungal isolates were screened on tannic acid medium. The highest tannase producer was selected and identified as Cryptococcus sp. NRC10 with homology level 99.9%. Medium II at 45°C for 24 h at pH 5 were the most favourable conditions required for maximum enzyme production. Glucose and NH4 Cl were the best carbon and nitrogen sources, respectively. The best conditions for the purified enzyme were 0.20 % of tannic acid and 0.15 ml of tannase enzyme at 45°C after 10 minutes with pH 6. The addition of Mn2+ stimulated the enzyme activity. The purified enzyme was used for the degradation of tannins in Red Sea water and green tea leaves samples. The amount of tannins after tannase addition was decreased. In conclusion, tannase has a role in the removal of tannins in contaminated water and soil. [ABSTRACT FROM AUTHOR]

Clean-up of contaminated wastewater remains to be a major challenge in petroleum refinery. Here, we describe the capacity of a bacterial consortium enriched from crude oil drilling site in Al-Khobar, Saudi Arabia, to utilize polycyclic aromatic hydrocarbons (PAHs) as sole carbon source at 60°C. The consortium reduced low molecular weight (LMW; naphthalene, phenanthrene, fluorene and anthracene) and high molecular weight (HMW; pyrene, benzo(e)pyrene and benzo(k)fluoranthene) PAH loads of up to 1.5 g/L with removal efficiencies of 90% and 80% within 10 days. PAH biodegradation was verified by the presence of PAH metabolites and evolution of carbon dioxide (90 ± 3%). Biodegradation led to a reduction of the surface tension to 34 ± 1 mN/m thus suggesting biosurfactant production by the consortium. Phylogenetic analysis of the consortium revealed the presence of the thermophilic PAH degraderPseudomonas aeruginosastrain CEES1 (KU664514) andBacillus thermosaudia(KU664515) strain CEES2. The consortium was further found to treat petroleum wastewater in continuous stirred tank reactor with 96 ± 2% chemical oxygen demand removal and complete PAH degradation in 24 days. [ABSTRACT FROM AUTHOR]

In this study, the bacterial strain CEES 33 was isolated from the coastal area of the Red Sea, Jeddah, Kingdom of Saudi Arabia. The bacterium isolate was identified and characterized by using biochemical and molecular methods. The isolate CEES 33 has been identified as Gram-negative rod shaped and cream pigmented spherical colonies. It also demonstrated a positive result for nitrate reduction, oxidase, catalase, citrate utilization, lipase and exopolysaccharide production. Strain CEES 33 was characterized at the molecular level by partial 16S rRNA sequencing and it has been identified as Marinobacter lipolyticus (EMBL LN835275.1). The lipolytic activity of the isolate was also observed 2.105 nkatml-1. Furthermore, the bacterial aqueous extract was used for green synthesis of silver nanoparticles (AgNPs), which was further confirmed by UV-visible spectra (430 nm), XRD and SEM analysis. Moreover, the biological functional group that involved in AgNPs synthesis was confirmed by FTIR spectra. The biological activities of AgNPs were also investigated, which showed a significant growth inhibition of Candida albicans with 16 ± 2 mm zone of inhibition at 10 μg dose/wells. Therefore, bacterium Marinobacter lipolyticus might be used in future for lipase production and nanoparticles fabrication for biomedical application, to control fungal diseases caused by C. albicans. [ABSTRACT FROM AUTHOR]