Characterization of Alcaligenes faecalis GPA-1 producing thermostable extracellular α-amylase

The bacterium coded GPA-1(isolated by Dr V Thankamani in 1990) was characterizedby standard methods including microscopy, special stains, biochemical tests and growth onvarious types of media for systematic identification up to genus level. With 16S rRNA genesequencing, the isolate was identified as Alcaligenes faecalis and deposited in NCBI withGenBank Accession number HQ 848384. The isolate was screened for the production ofenzymes like amylase, protease and carboxy methyl cellulase (CMC). This isolate showed aclear zone of lysis on starch agar, yellow zone on CMC agar when stained with Congo redand a clear zone of casein hydrolysis in skim milk agar indicating amylase, cellulose andproteolytic activity respectively. Preliminary characterization of extra cellular amylase wasdone. The strain was found to be alkalophilic as it grew well in pH 9.0 and 10.0. Theoptimum temperature and salinity were found to be 37oC and 3% respectively. Growth curveexperiments of the organism in nutrient broth containing 1% starch at varying physical andnutritional parameters were done up to 72 hrs, and the samples were also tested for pHchanges, biomass, total protein, reducing sugars and α-amylase activity. Soluble starch (1%)in standard nutrient broth and pH 8.0, 37oC, shaking at100 rpm and 40-44 hours incubationwere found to be the optimum conditions for maximal enzyme production.