Biovalorizing agro-waste 'de-oiled rice bran' for thermostable, alkalophilic and detergent stable α-amylase production with its application as laundry detergent additive and textile desizer.

The current research was concerned with the use of abundant agro-waste 'de-oiled rice bran (DORB)' as a sustainable substrate to produce α-amylase followed by several targets like process parameter optimization for augmented production and immobilization. In addition, we have also focused on investigating the application of DORB_amy as an efficient laundry detergent additive and textile desizer. The best production was recorded at pH 8.0 at 37 °C after 96 h incubation with 1.5 % (w/v) maltose. The DORB_amy has optimum activity at pH 9.0 at 60 °C with a Km and Vmax of 0.31 mg/mL and 222.22 mg/mL/min respectively. The catalytic performance of DORB_amy was further enhanced after immobilization in 3.0 % calcium alginate beads with 61.95 ± 0.17 % of operational stability after five continuous reaction cycles. The findings showed excellent performance of DORB_amy in cleaning starchy stains. The washing performance of enzyme and detergent together was better than their individual performance which increases the application of α-amylase as a laundry detergent additive. About 17.34 % weight loss or desizing was done by DORB_amy with an 8-9 TEGEWA rating. The reported biochemical features like thermostability, alkalophilic and detergent-stable nature of the DORB_amy make it industrially fit with great significance.

Molecular strategies to enhance stability and catalysis of extremophile-derived α-amylase using computational biology.

α-Amylase is the most significant glycoside hydrolase having applications in various industries. It cleaves the α,1-4 glucosidic linkages of polysaccharides like starch, glycogen to yield a small polymer of glucose in α-anomeric configuration. α-Amylase is produced by all the three domains of life but microorganisms are preferred sources for industrial-scale production due to several advantages. Enormous studies and research have been done in this field in the past few decades. Still, it is requisite to work on enzyme stability and catalysis, as it loses its functionality in extreme. As the enzyme loses its structural and catalytic property under extreme environmental conditions, it is mandatory to confer some potential strategies for enhancing enzyme behaviour in such conditions. This limitation of an enzyme can be overcome up to some extent by extremophiles. They serve as an excellent source of α-amylase with outstanding features. This review is an attempt to encapsulate some structure-based strategies for improving enzyme behaviour thereby enabling researchers to selectively amend any of the strategies as per requirement during upstream and downstream processing for higher enzyme yield and stability. Thus, it will provide some cutting-edge strategies for tailoring α-amylase producing organism and enzyme with the help of several computational biology tools.

Aspects and Recent Trends in Microbial α-Amylase: a Review.

α-Amylases are the oldest and versatile starch hydrolysing enzymes which can replace chemical hydrolysis of starch in industries. It cleaves the α-(1,4)-D-glucosidic linkage of starch and other related polysaccharides to yield simple sugars like glucose, maltose and limit dextrin. α-Amylase covers about 30% shares of the total enzyme market. On account of their superior features, α-amylase is the most widely used among all the existing amylases for hydrolysis of polysaccharides. Endo-acting α-amylase of glycoside hydrolase family 13 is an extensively used biocatalyst and has various biotechnological applications like in starch processing, detergent, textile, paper and pharmaceutical industries. Apart from these, it has some novel applications including polymeric material for drug delivery, bioremediating agent, biodemulsifier and biofilm inhibitor. The present review will accomplish the research gap by providing the unexplored aspects of microbial α-amylase. It will allow the readers to know about the works that have already been done and the latest trends in this field. The manuscript has covered the latest immobilization techniques and the site-directed mutagenesis approaches which are readily being performed to confer the desirable property in wild-type α-amylases. Furthermore, it will state the inadequacies and the numerous obstacles coming in the way of its production during upstream and downstream steps and will also suggest some measures to obtain stable and industrial-grade α-amylase.