Valorization of lignocellulosic waste using Halothermophilic Bacillus sp.: A sustainable approach for the production of glycoside hydrolase

Abstract

Abstract The primary sector of Pakistan’s economy is agriculture. A huge number of agriculture industries are currently operating in all provinces of Pakistan. However, the various procedures in agriculture industries release abundant amount of waste that accumulate in environment therefore causing pollution. The approaches of industrial biotechnology give solution of environmental pollution by effective consumption of these waste residues in to industrially important metabolites especially enzymes through microbial fermentation in ecofriendly manner. In microbial domain, bacterial cells are largely used for the production of different enzymes specifically starch degrading enzymes. Among them, glycoside hydrolase is well known to be secreted extracellularly in adequate quantities. An important category of glycoside hydrolase is amylase. Amylases possess huge number of industrial applications as they are utilized in various processes of food, textile, paper, detergent, leather, starch, pharmaceutical and fuel industries. The current study was based on the utilization of several lignocellulosic substrates for the production of amylase by indigenously isolated halothermophilic Bacillus subtilis C5W. Parametric optimization resulted in the production of maximum amylase in a modified starch production medium. Enhanced enzyme yield was attained at 50 °C after 24 hours of incubation period in modified culture medium (pH 7.0). For nutritional requirement of isolate for enhanced production of amylase, various agro-industrial wastes were used as a carbon source along with soluble starch as a control. Rice husk greatly induced amylase production (57.5%) among all agro substrates. Although starch (1.5%) provoked maximum production of amylase as it is in purified form but consumption of agro-industrial biomass significantly enhanced amylase production. Other chemical components like peptone (0.05%) as an organic nitrogen source and NaCl (1%) was also associated with improved production of enzyme. The ability of isolated Bacillus specie to sustain in wide pH ranges with least fermentation time makes it as a potential candidate for mass production of amylase. Moreover, the potential usage of agro industrial substrates for cultivation of amylase reduces cost of fermentation media and production setups.