Isolation and Characterization of Bacillus Subtilis KC3 for Amylolytic Activity

Abstract

Abstract-Microbial α-amylase is a highly demanded industrial enzyme with extensive commercial applications in various sectors. Studies were carried out with a bacterial strain producing extracellular α-amylase, isolated from rhizospheric soil of Euphorbia hirta. The isolate was gram positive, motile rod, bearing terminal endospore. It exhibited >98% similarity with the reference strains in the GenBank. The phylogenetic tree constructed on the basis of 16S rRNA gene sequences revealed that it clustered with the closest members of Bacillus subtilis and identified as Bacillus subtilis KC3. Furthermore, the effects of incubation period, temperature, pH, different carbon and nitrogen sources, metal salts and different substrate concentrations of the medium were optimized. The maximum enzyme production was found after 48 h (22.92 U/ml) of incubation at temperature 40°C and pH 7. The optimal temperature and pH for enzyme activity were 50°C and 6.5 respectively. Barley starch (27.27 U/ml) was observed to be the best inducer followed by corn starch (24.30 U/ml) and maltose (19.10 U/ml). The addition of glucose to the culture medium greatly reduced the synthesis of α-amylase (5.45 U/ml) which demonstrates that a classical glucose effect is operative in this organism. The effects of different metal ions (Ca 2+, Fe 2+ , Mg 2+ , Zn 2+ and Cu 2+ ) on amylolytic activity were investigated and it was found that 0.1% of Ca 2+ increased enzyme production (28.83U/ml), whereas other metal ions exhibited inhibitory effects. The enzyme production was maximum at 2% substrate (starch) concentration, which declined beyond it. These characteristics of Bacillus subtilis KC3, suggest that this is a promising isolate which merits further investigations for potential applications in various biotechnological processes.Index Terms-α-amylase, bacillus subtilis KC3, euphorbia hirta, rhizospheric soil

Molecular Identification of Newly Isolated Bacillus Strains from Poultry Farm and Optimization of Process Parameters for Enhanced Production of Extracellular Amylase Using OFAT Method

“…All the isolates except B. tequilensis strain ARMATI showed maximum amylase activity at 35°C. The finding of this present study is more or less similar to the reports of Vijayalakshmi et al (2012), who demonstrated that optimum Res. J.…”

“…A decline in amylase activity afterwards was probably due to depletion of nutrients in the fermentation medium of the microorganisms, causing stressed and unfavourable conditions for the bacteria resulting in reduction of enzyme activity. Our reports were against the findings of Vijayalakshmi et al (2012) and Deb et al (2013), who demonstrated maximum amylase activity by Bacillus sp. at 48 h of incubation.…”

“…Microbiol., 10 (9): 393-420, 2015 supplied oxygen for the cultivation of these particular strains in the fermentation medium. Agitation rates in the range of 100-250 rpm have also been reported for the production of alpha amylases (Vijayalakshmi et al, 2012;Santos and Martins, 2003). Incubation period is one of the most important parameter in metabolic activity and growth of bacteria.…”

“…Bacillus sp. is an industrial important microorganism because of its rapid growth rate, secretion of enzyme into the extracellular medium and safe handling (Vijayalakshmi et al, 2012). Bacillus subtilis, Bacillus amyloliquefaciens and Bacillus licheniformis are used as bacterial workhorses in industrial microbial cultivations for the production of a variety of enzymes as well as fine biochemicals (Deb et al, 2013).…”

Effect of Physical Parameters and Amino acids on the Oil degradation Activity of Bacteria Isolated from Oil Contaminated Sites

“…The optimal temperature required for maximum oil degradation activity by Bacillus and Acinetobacter species was 33 0 C and 35 0 C respectively ( Table 2). Bacillus subtilis KC3 had shown maximum growth at 33 0 C [14] and most of the Acinetobacter species show highest growth between temperatures 33-35 0 C [15] . The optimal temperature for Pseudomonas and Micrococcus species was found to be 31 0 C (Table 2).…”