Optimization of physicochemical parameters for maximum amylase production by indigenously isolated Bacillus cereus AS2 strain.

Amylases are enzymes that catalyze the hydrolysis of starch into highly valuable products of economic significance. Amylases are used extensively in various industrial sectors. Microbial sources particularly Bacillus species are well known for the cost effective commercial production of amylase enzyme. Present study focuses on the enhancement of amylase enzyme production from an indigenously isolated Bacillus cereus AS2 strain via one variable at a time (OVAT) optimization of different physical and chemical factors. Purposely, eight parameters possibly affecting the amylase production including temperature, pH, incubation time, inoculum size, substrate concentration, metal ions, carbon and nitrogen sources were investigated. According to the results, amylase production was significantly boosted at maximum when the Bacillus cereus AS2 was grown at 45°C on pH 7.0 for 72 hours in the medium supplemented with 4% starch and 0.5% glycine. Among the different metal ions tested, CaCl2 (0.05%) was found significant to accelerate extracellular amylase production.

Industrially relevant cellulase production by indigenous thermophilic Bacillus licheniformis TLW-3 strain: Isolation-molecular identification and enzyme yield optimization.

Cellulases are the third largest single industrial bio-robots. These enzymes are employed in industries like pharmaceutical, textile, food processing, paper recycling and detergent manufacturing. In order to produce broadly diversified cellulases, microbes (both bacteria and fungi) have been exploited. Different ecological niches have already been explored for the isolation of cellulolytic microbes. However, there have been no remarkable reports viz a viz to the hot oven ash (for cellulolytic bacterial flora). In this regard, a Bacillus strainTLW-3 was isolated and selected for CMCase production and optimization. The strain was identified as B. licheniformis TLW-3 through 16S rDNA sequencing that was submitted to Gen Bank with accession numberKY440432. The isolate growth and CMCase production conditions were optimized to get the maximum CMCase yield. The highest growth and maximum CMCase production by B. licheniformis TLW-3 were recorded at pH 7 and 50ºC, after the incubation period of 72 (hour) at 150rpm. Studies on the various nitrogen and carbon sources on CMCase production showed that the medium having 1% peptone, 0.5% yeast extract and 1% CMC can significantly enhance the enzymatic yield as compared to other (studied) sources. EDTA, Tween-20 and Tween-80 acted as inhibitors for the enzyme production. The present study holds the conviction that the (reported) organism could directly be applied to produce industrial thermophilic CMCase.

Industrially important hydrolytic enzyme diversity explored in stove ash bacterial isolates.

Extreme environments merit special attention and significance because of the possible existence of thermophilic microorganisms in such ecological niches. Keeping this in mind indigenous stove ash samples were explored for extremophilic bacteria in term of their biodiversity. Accordingly, this study reports 37 bacterial isolates from the local wood run oven (Tandoor) ash samples. All the isolated strains belong to genus Bacillus on the bases of morpho-cultural and biochemical considerations. The average temperature tolerance profile was >45°C thereby, indicating towards the thermophilic nature of the isolated strains. The Bacillus isolates were screened for 10 different hydrolytic enzymes (cellulase, xylanase, amylase, pectinase, caseinase, keratinase, lipase, esterase, dextranase and ß-galactosidase) by plate screening method using the medium incorporated with specific substrate(s). It was found that keratinase was produced by all the isolates while, 36 (97.2%) isolates showed caseinase and esterase production. Amylase was produced by 35(94.6%) isolates and 34 (91.8%) isolates were able to degrade Tween-80 and xylan as substrate for lipase and xylanase respectively. The enzyme, ß-galactosidase was produced by 31 (89.1%) of the isolates. Cellulase and dextranase were produced by 26 (70.2%) and 22 (59.4%) isolates respectively. None of the isolates could (under the existing conditions) produce pectin-hydrolyzing enzyme. According to the Tukey's post hoc test, significant difference was found between the mean enzyme index of all the (screened) enzymes. Thus, the isolated bacterial strains with diverse hydrolytic potential may be of great value and relevance for the existing (national) industrial setups.