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Expression of esterase gene in yeast for organophosphates biodegradation
Kambiranda, Devaiah M.,Asraful-Islam, Shah Md.,Cho, Kye Man,Math, Renukaradhya K.,Lee, Young Han,Kim, Hoon,Yun, Han Dae Elsevier 2009 Pesticide biochemistry and physiology Vol.94 No.1
<P><B>Abstract</B></P><P>Organophosphates are esters of phosphoric acid and can be hydrolyzed and detoxified by carboxylesterase and phosphotriesterase. In this work esterase enzyme (Est5S) was expressed in yeast to demonstrate the organophosphorus hydrolytic activity from a metagenomic library of cow rumen bacteria. The esterase gene (<I>est</I>5S) is 1098bp in length, encoding a protein of 366 amino acid residues with a molecular weight of 40kDa. Est5S enzyme was successfully produced by <I>Pichia pastoris</I> at a high expression level of approximately 4.0g L<SUP>−1</SUP>. With <I>p</I>-nitrophenol butyrate as the substrate, the optimal temperature and pH for enzyme activity were determined to be 40°C and pH 7.0, respectively. The esterase enzyme was tested for degradation of chlorpyrifos (CP). TLC results obtained inferred that CP could be degraded by esterase enzyme (Est5S) and HPLC results revealed that CP could be efficiently degraded up to 100ppm. Cadusafos (CS), coumaphos (CM), diazinon (DZ) dyfonate (DF), ethoprophos (EP), fenamiphos (FM), methylparathion (MPT), and parathion (PT) were also degraded up to 68, 60, 80, 40, 45, 60, 95, and 100%, respectively, when used as a substrate with Est5S protein. The results highlight the potential use of this enzyme in the cleanup of contaminated insecticides.</P>
Kye Man Cho,Devaiah M Kambiranda,Seong Weon Kim,Renukaradhya K Math,Woo Jin Lim,Su Young Hong,Han Dae Yun 한국식품과학회 2008 Food Science and Biotechnology Vol.17 No.6
Kimbab is the most popular ready-to-eat (RTE) food in Korea. A rapid detection method based on multiplex PCR technique was developed for detection of major food-borne pathogens like Salmonella spp., Shigella spp., Bacillus cereus, Listeria monocytongenes, and Staphylococcus aureus. Specific bands were obtained as 108 bp (Sau, S. aureus), 284 bp (Sal, S. enterica, S. enteritids, and S. typhmurium), 404 bp (Lmo, L. monocytogenes), 475 bp (Bce, B. cereus), and 600 bp (Shi, S. flexineri and S. sonnei). Visible cell numbers varied from 4.14-5.03, 3.61-4.47, and 4.10-5.11 log CFU/g in randomly collected June, July, and August samples, respectively. Among the 30 kimbab samples obtained 83.3% samples were contaminated and 16.7% samples were free from contamination. The highest rate of contamination was with S. aureus (56.7%) followed by B. cereus (43.3%), Salmonella spp. (36.7%), Shigella spp. (13.3%), and L. monocytogenes (6.7%). The identification of the pathogenic species could be faster using one polymerase chain reaction (PCR) and the ability to test for food-borne pathogenic species in kimbab will save time and increase the ability to assure its quality.
Cho, Kye-Man,Lee, Sun-Mi,Math, Renukaradhya K.,Islam, Shah Md. Asraful,Kambiranda, Devaiah M.,Kim, Jong-Min,Yun, Myoung-Geun,Cho, Ji-Joong,Kim, Jong-Ok,Lee, Young-Han,Kim, Hoon,Yun, Han-Dae The Korean Society for Microbiology and Biotechnol 2008 Journal of microbiology and biotechnology Vol.18 No.12
Bacterial diversity and the composition of individual communities during the composting process of swine and mushroom cultural wastes in a field-scale composter (Hazaka system) were examined using a PCR-based approach. The composting process was divided into six stages based on recorded temperature changes. Phylogenetic analysis of eighty 16S rRNA sequences from uncultured composting bacterial groups revealed the presence of representatives from three divisions, including plant pathogenic bacteria, high-molecule-degrading bacteria and spore-forming bacteria. The plant pathogen A. tumefaciens gradually decreased in abundance during the composting process and eventually disappeared during the thermophilic and cooling stage. A bacterium homologous to Bacillus humi first appeared at the early thermophilic stage and was established at the intermediate thermophilic, post-thermophilic, and cooling stages. It was not possible to isolate the B. humi during any of the stages using general culture techniques.