Enhancement of alpha amylase production by Aspergillus flavus AUMC 11685 on mandarin (Citrus reticulata) peel using submerged fermentation

Mandarin peel as submerged fermentation (SmF) source was tested for the production of alpha amylase enzyme by strain of Aspergillus flavus AUMC 11685. Incubation period, concentration of substrate, temperature, pH and size of inoculum were optimized to achieve the maximum production of alpha amylase enzyme by Aspergillus flavus using mandarin peel. The maximum production of alpha amylase enzyme by Aspergillus flavus was recorded at 4-5 days of incubation, 3% substrate concentration, inoculum concentration 10%, temperature 28-40°C and pH 4-5.5. DOI: http://dx.doi.org/10.5281/zenodo.81827

Comparative molecular studies of halophilic bacteria from saline water and soil in the Saudi environment

Halophilic bacteria are a microorganism that grows optimally in the presence of the very high concentration of sodium chloride. Halophiles are vital sources of various enzymes including hydrolases, which are very stable and catalytically highly efficient at high salt concentration and other extreme conditions such as high temperature, pH and presence of organic solvents.  Several hydrolases such as amylases, proteases, and lipases have been obtained from halophilic bacteria and are commonly used for various industrial applications. We initiated a screening project to isolate and characterize the halophilic bacteria from the Red Sea, which is one of the saltiest bodies of water in the world. Water and soil samples, collected from the Red Sea coast, Jeddah, Saudi Arabia, were screened for isolation of halophilic bacteria. Ten bacterial isolates were obtained, which were characterized by biochemical tests and 16S rRNA gene sequencing. Hydrolase producing bacteria among the isolates were screened by plate assay on starch and gelatin agar plates for amylase and protease, respectively.  Two bacterial isolates i.e Bacillus haynesii and Enterobacter cloacae subsp. were found to possess significant amylase and protease activity. Further characterization of both the strains is in progress

Isolation and identification of bacterial consortia responsible for degrading oil spills from the coastal area of Yanbu, Saudi Arabia

Twenty-three crude-oil-degrading bacteria were isolated from oil-contaminated sites near the Red Sea. Based on a high growth rate on crude oil and on hydrocarbon degradation ability, four strains were selected from the 23 isolated strains for further study. These four strains were selected on the basis of dichlorophenolindophenol assay. The nucleotide sequences of the 16S rRNA gene showed that these isolated strains belonged to genus Pseudomonas and Nitratireductor. Among the four isolates, strains S5 (Pseudomonas sp., 95%) and 4b (Nitratireductor sp., 70%) were the most effective ones in degrading crude oil. Using a spectrophotometer and gas chromatography–mass spectrometry, degradation of more than 90% of the crude oil was observed after two weeks of cultivation in Bushnell–Haas medium. The results showed that these strains have the ability to degrade crude oil and may be used for environmental remediation

Enhancement of alpha amylase production by Aspergillus flavus AUMC 11685 on mandarin (Citrus reticulata) peel using submerged fermentation

Mandarin peel as submerged fermentation (SmF) source was tested for the production of alpha amylase enzyme by strain of Aspergillus flavus AUMC 11685. Incubation period, concentration of substrate, temperature, pH and size of inoculum were optimized to achieve the maximum production of alpha amylase enzyme by Aspergillus flavus using mandarin peel. The maximum production of alpha amylase enzyme by Aspergillus flavus was recorded at 4-5 days of incubation, 3% substrate concentration, inoculum concentration 10%, temperature 28-40°C and pH 4-5.5. DOI: http://dx.doi.org/10.5281/zenodo.81827

Characterization of native fungi responsible for degrading crude oil from the coastal area of Yanbu, Saudi Arabia

A total of 15 fungal isolates were obtained from oil-contaminated sites near the Red Sea in the Yanbu region. Based on the preliminary DCPIP (2,6-dichlorophenolindophenol) assay, three isolates showed promising oil degrading ability. The next-generation sequencing of the ITS-I and ITS-II internal transcribed spacer regions assigned the isolates to Aspergillus and Penicillium. Among these three strains, Y2 (Aspergillus oryzae) was the most efficient, degrading about 99% of the crude oil. The degradation rates were corroborated using spectrophotometric and gas chromatography–mass spectrometry analyses after two weeks of cultivation in Bushnell–Haas medium. All the three strains proved to be potent oil-degrading strains and, hence, can be utilized to degrade oil contaminants

Anti-bacterial activity of Ricinus communis L. against bacterial pathogens Escherichia coli and Klebsiella oxytoca as evaluated by Transmission electron microscopy

The emergence of multidrug-resistant (MDR) microbes has become one of the major threat globally. Infectious diseases are the second leading cause of death, two-third of which are caused by Gram-negative bacteria. The increasing number of multidrug resistant (MDR) microbes is quite alarming and has raised the necessity of development of new antibacterial drugs. Escherichia coli and Klebsiella have been reported among the top most resistance-developing pathogens. Ricinus communis is an important medicinal plant reported to possess antimicrobial phytochemicals such as α-pinene. The hexane treated crude ethanolic extract of R. communis was evaluated against Gram-negative bacteria E. coli and Klebsiella oxytoca. The agar well diffusion assay was used to determine the antibacterial activity. In the present study, we have shown experimentally that leaf extract of R. communis can induce the deterioration of the inner and outer cell membranes of E. coli and K. oxytoca and decrease their viability at a concentration of 50 mg/ml. Transmission electron microscopic results revealed cell membrane damage, cellular disintegration and release of cytoplasmic content, leading to cell death. To our knowledge, this is the first study of the antibacterial activity of R. communis against E. coli and K. oxytoca by Transmission electron microscopy. The ultramicroscopic observations showed that the phytochemical present in the leaf extract of R. communis could penetrate the bacterial cell, causing rupture of cell membranes and hence confirm the cytotoxic and antimicrobial property of R. communis

Gene expression profiling to elucidate the pharmacological and toxicological effects of Ricinus communis L. leaf extract in mammalian cells

Ricinus communis is a traditional medicinal plant which has been utilized for centuries for treatment of various conditions. Due to the presence of diverse phytochemicals, Ricinus is an outstanding natural resource to discover new drugs for various diseases such as diabetes, cancer, arthritis, ulcer and asthma. In this study, we performed whole-genome gene expression profiling using RNA-Seq to determine the differentially expressed genes in a mammalian cell line after exposure to Ricinus leaf extract and elucidate their pharmacological effects in order to support its ethnomedicinal uses. Various genes involved in cancer, inflammation, atherosclerosis and diabetes were found to be differentially regulated after exposure to sub-lethal concentrations of the Ricinus extract in MCF7 cells. An important gene involved in cancer progression and metastasis, that is, PIK3R3 (Phosphatidylinositol 3-kinase regulatory subunit gamma), was downregulated in MCF7 cells after treatment with Ricinus extract. PIK3R3 is an important component of the PI3K/AKT signalling pathway which is essential for cell proliferation, angiogenesis, inhibition of apoptosis and metastasis to distant organs. The Ricinus extract downregulated the expression of DPP4 (Dipeptidyl peptidase-4) and upregulated the expression of PPAR-γ (Peroxisome proliferator-activated receptor gamma) which are crucial in controlling blood glucose levels. Expression of TNFAIP6 (Tumor necrosis factor-inducible gene 6), which is shown to mediate anti-inflammatory and protective effects, was increased after treatment with Ricinus extract. We also analyzed the genes which might also confer toxicity. Our gene expression profiling data corroborate the potential therapeutic benefits of Ricinus communis plant