Production of amylase from Bacillus subtilis sp. strain KR1 under solid state fermentation on different agrowastes

Amylolytic microorganisms from diverse tropical environments: Isolation, identification, and amylase production

“…The specific enzyme activity of the extracellular enzymes produced by the isolates ranged between 0.0079 and 0.0629 U g −1 . These values were lower compared with those of a commercial amylase enzyme (1.7188 U g −1 ) that was used as a control and others reported in the literature [17,25,29]. The higher enzyme activity by the control over the isolate sample enzymes could be because the control is a purified enzyme unlike the samples, which were crude enzymes.…”

“…This is because the purity level of an enzyme affects its specific activity, which is expressed as the ratio of the enzyme activity to the concentration of the protein used during the enzymatic activity assay [25]. The values obtained in this study are also lower than those of Bacillus strains reported by Pranay et al [17] (13.68–18.20 U g −1 ) and Luang‐In et al [14] (0.21–0.91 U g −1 ) but in the same range of the Bacillus amyloliquefaciens reported by Abd‐Elhalem et al [29]. The reasons for lower/varied specific activity could be enzyme production and assay conditions, such as pH and temperature, were not optimized in this study.…”

“…The SHR ranged from 1.6 to 6.0 for 17 isolates, which indicated that they fell into the category of excellent amylase producers. The SHR ratios were diverse (1.6–6.0) compared with 3.4–4.0 reported by VaseeKaran et al [27], 2.7–8.3 reported by Pranay et al [17], and 1.5 reported by Alkando and Ibrahim [28] for B. licheniformis . The results from this study indicated that the isolates produced amylases with varying amylolytic potentials.…”

“…Members of the Bacillus genera ( B. subtilis , B. stearothermophilus , B. amyloliquefaciens , B. licheniformis , B. coagulans , B. polymyxa , B. mesentericus , B. vulgaris , B. megaterium , B. cereus , B. halodurans , and Bacillus spp . Ferdowsicous ) are also the most used isolated and used organisms for amylase production [14,17]. Lysinibacillus spp.…”

“…Excess Lugol's iodine reagent was drained off by distilled water and the plates were observed for the formation of a clear halo zone around the colonies against a blue‐black background. A clear halo zone around the coloniesx indicated amylase production and was used for the determination of starch hydrolysis ratio (SHR) as indicated in Equation () [16,17]. SHR was used for the ranking of the hydrolysis potential of the amylases produced by the isolates.…”