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Abstract:
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Bacillus smithii BTMS 11, isolated from marine
sediment, produced alkaline and thermostable lipase.
The enzyme was purified to homogeneity by ammonium
sulfate precipitation and ion exchange chromatography
which resulted in 0.51 % final yield and a 4.33 fold of
purification. The purified enzyme was found to have a
specific activity of 360 IU/mg protein. SDS-PAGE analyses,
under non-reducing and reducing conditions, yielded a
single band of 45 kDa indicating the single polypeptide
nature of the enzyme and zymogram analysis using methylumbelliferyl
butyrate as substrate confirmed the lipolytic
activity of the protein band. The enzyme was found to have
50 C and pH 8.0 as optimum conditions for maximal
activity. However, the enzyme was active over wide range
of temperatures (30–80 C) and pH (7.0–10.0). Effect of a
number of metal salts, solvents, surfactants, and other
typical enzyme inhibitors on lipase activity was studied to
determine the novel characteristics of the enzyme. More
than 90 % of the enzyme activity was observed even after
3 h of incubation in the presence of commercial detergents
Surf, Sunlight, Ariel, Henko, Tide and Ujala indicating the
detergent compatibility of B. smithii lipase. The enzyme
was also found to be efficient in stain removal from cotton
cloths. Further it was observed that the enzyme could
catalyse ester synthesis between fatty acids of varying
carbon chain lengths and methanol with high preference for
medium to long chain fatty acids showing 70 % of esterification.
Results of the study indicated scope for application
of this marine bacterial lipase in various industries |