Screening and Characterization of Serine Racemase Producing Microbes and In Silico Evolutionary Studies of Serine Racemase

Abstract

Serine racemase (SR) is bifunctional, PLP dependent belonging to the fold type II enzyme newlinefamily. In the racemization of D-serine and dehydration, pyruvate is produced from L-serine. newlineStudies witnessed the presence and biological role of D-serine and SR in both prokaryotes and newlineeukaryotes. It is a well-recognized regulator of various activities in the human nervous system. newlineIn plants, it has a role in the nitrogen cycle regulation and pollen tube growth. Serine newlineenantiomers are present in different concentrations and few bacterial strains are reported to newlinecontribute to D-serine in the environment. D-amino acids, the important components of the newlinebacterial cell walls, are valuable molecular and genetic markers of bacterial-derived organic newlinematerial in the environment. Moreover, bacteria could be a valuable serine racemization tool newlinefor various industrial and environmental applications. During the present study, soil samples newlinefrom different places in North India were collected and processed to isolate and screen the newlinebacteria on M9 minimal media (Himedia) for D-serine synthesis. Thin-layer chromatography newline(TLC Silica gel 60 F 254 (20 X 20cm, Merck, Darmstadt, Germany) and Mass spectroscopic newlineanalysis (Bruker MICROTOF II spectrometer) studies, etc were performed. D-serineproducing isolates were characterized as per standard procedures. Bacterial isolate A1C1 with newlinemaximum D-serine (0.919±0.02 nM) synthesis (isolate grown at 37and#8451;±0.5, 150±0.5 RPM, and newline7±0.5pH for 48hrs of incubation time) was identified as Bacillus tequilensis based on 16sRNA newline