No abstract

No abstract

Bio-ethanol is considered as an important renewable fuel to partly replace fossil-derived fuels. In this study, bioethanol production, which includes cellulase production, saccharification of the cellulose content of sesame seed residue, and ethanol production, was investigated. Out of the hundreds of cellulase-producing bacterial strains isolated from sesame seed residue during this study, the B isolate was found to have the highest cellulase enzyme production. This isolate was identified as Bacillus cereus by 16S rRNA sequencing. The effects of different growth parameters, including inoculum concentration, incubation time, temperature, pH, and carbon and nitrogen sources, were investigated to optimize the growth conditions of the bacterifum. The maximum cellulase activity was achieved with an inoculum concentration of 3% after 48 h in a basal medium at a pH of 7 and an incubation temperature of 35 °C. The best nitrogen and carbon sources were yeast extract and sesame seed residue, respectively. The results showed the liberation of 2.3 g/L of reducing sugar by the dinitrosalicylic acid method. This total reducing sugar produced 15 g/L of ethanol after 48 h when Saccharomyces cerevisiae was used as a fermentation agent. Hence, bioethanol was successfully produced from the cellulose of sesame seed residue using the cellulase enzyme from B. cereus.

Objectives: This study aims to characterize the gene encoding halo tolerant amylase of bacteria isolated from Jazan region. Materials and Methods: Soil samples were collected from several area of Jazan region, KSA. The samples were serially diluted and plateted on starch agar plates. The amylase producing bacteria were detected by iodine test. To determine the halophilic amylase producing bacteria, several colonies were tested for their ability to grow at higher concentrations of NaCl ranging from 7 to 16%. The bacteria was identified by 16S rRNA and the full length amylase gene was fully identified by sequencing using specific primers. Results: One bacterial halophilic isolate was able to grow on starch agar medium up to 14% NaCl. The Gram stain of the isolate indicated that it is Gram-positive, bacilli. The 16S rRNA gene homology study showed that the bacterial isolate was identified as Bacillus paralicheniformis. Two specific primers were designed named S1F, S1R, to amplify the amylase gene (AMY) region using PCR and the PCR product was sequenced. The sequencing results showed that the full-length amy gene of B. paralicheniformis was of 1452 encoding 483 amino acids. The expected M.Wt. of the protein expressed is of 55 KDa. Conclusion: We report the isolation, identification, and characterization of an isolate of halophilic bacterium isolated from Jazan region. Based on molecular identification, this isolate was identified as Bacillus paralicheniformis. This bacterial strain has an α-amylase gene in its genome and is able to produce extracellular α-amylase. Based on the findings of this work we propose that Bacillus paralicheniformis amy gene could be cloned into expression vector for large scale production.