Characterization of an alkaline endo-α-1-4-amylase from alkaliphilic Bacillus halodurans LBW 5117 and demonstration of its desizing potential

Abstract

The demand for amylases with improved storage and operational properties for the economical production of textiles has been on the rise in recent years. An alkaline amylase (Amy LBW 5117) from alkaliphilic Bacillus halodurans LBW 5117 was characterized and used to desize woven cotton. The enzyme had a shelf life of 6 weeks when stored at 4-30°C. It exhibited pH and temperature optima of 10 and 60 o C, respectively. Its activity was stimulated or insignificantly affected by up to 10 mM K + , Ca 2+ , Mg 2+ , Fe 3+ , Na + , and Zn 2+ , as well as Cu 2+ (≤1.0 mM), but was partially inhibited by Mn 2+ (0.5 mM). The enzyme lost all of its activity after 3 h of incubation at 60°C, but this improved to 96% in the presence of 1.0 mM Ca 2+ and 0.05 mM Tween 20. The enzyme was cellulase-free and hydrolyzed starch in an endo-fashion. Furthermore, it degraded and eliminated 8.2% starch size from woven cotton and yielded a fabric that exhibited a TEGEWA rating of 7-8 (residual starch content = 0.0725%) under its optimum operating conditions. This shows that Amy LBW 5117 has good storage and operational properties that potentially make it an effective desizing agent. ARTICLE HIGHLIGHTSAmy LBW 5117 is an alkaline endo-α-1-4-amylase that can desize woven cotton.• At high pH, implying less contamination from neutrophils.• At low temperatures, implying low-energy costs.• In the presence of metal ion impurities, implying savings on the purchase of chelators.