The temperature adaptation of α-amylase can be gained by different adjustments in protein structure with consecutive effects on the stability and flexibility of the protein. In this review, meso, thermo and cold-active α-amylases have been compared with respect to their structure and intramolecular interactions. With decrease in temperature, the number of ionic interactions also decreases, leading to greater flexibility of proteins. It has also been observed that the proline and arginine content is higher in thermophilic amylases as compared to meso and psychrophilic amylases, increasing the rigidity and structural stability of protein molecule.

Pectinases are among the most widely distributed enzymes in bacteria, fungi, and plants. Almost all the commercial preparations of pectinases are produced from fungal sources. Mucor circinelloides ITCC-6025 produced polygalacturonase when grown in Riviere's medium containing pectin (methyl ester) as the sole source of carbon. Immobilization of purified polygalacturonase was done on silica gel with 86% efficiency. The enzyme took 60 Min to bind maximally on the support. The immobilized enzyme showed maximum activity at a temperature of 45°C (4.57 U/mg) and pH 5.4. The immobilized enzyme was reused for four cycles as it retained almost 55% of its activity. The immobilized enzyme treatment increased the formation of higher alcohols and phenolics during the course of wine formation from apple and plum juices, whereas there was a decrease in the amount of carbohydrates. The enzyme treatment also resulted in clarification of wine; there was an increase in transmittance at 650 nm (201.78% in the case of apple wine and 223.4% in the case of plum wine) as compared to the control (untreated wine).

Amylases are of great significance in present day biotechnology. They constitute 25% of the industrial market.To meet the industrial demand there is a need of production optimization of ?-amylase from the microbialsource. In the present study, an attempt was made to isolate thermophilic bacterial strain producingthermophilic and alkaliphilic ?-amylase. Among 23 isolates, isolate K7 gave maximum production of ?amylase, which was later identified as Bacillus licheniformis. The organism gave maximum production of ?amylase in medium containing g/l (w/v) beef extract 3.0, peptone 5.0 and starch 1.0%. Starch (1.75%, w/v) andpeptone (0.15%, w/v) were optimized to be best carbon and nitrogen sources for ?-amylase production fromBacillus licheniformis. Optimum production of the enzyme was observed when inoculated medium of pH 8.0was incubated at 50°C for 48 h of incubation time.Further during optimization of reaction conditions, theenzyme gave maximum activity with 0.1 M Tris HCl buffer of pH 8.0 when incubated at a reactiontemperature of 50°C for 10 min of incubation time. The enzyme showed high affinity towards starch (0.15%,w/v) as substrate. The thermophilic and alkaliphilic nature of the enzyme suggest its potential application instarch, detergent and textile industries

Background: The most widely used thermostable enzymes are the amylases in the starch industry. These are among the most important enzymes and are of great significance in present day biotechnology. Objective: The main objective of the present study was to enhance α-amylase production from Bacillus licheniformis using Response Surface Methodology (RSM) and the purification of the enzyme to homogeneity. Method: Bacterial culture producing α-amylase and isolated from hot spring (Himachal Pradesh) was identified as Bacillus licheniformis using 16S rDNA gene sequencing (NCBI Accession No.: KR340466). Medium components and pysical culture parameters viz. pH, temperature, inoculum size, peptone concentration and starch concentration were optimized using RSM. Among these five factors, three factors (starch concentration, peptone concentration and inoculum size) had positive effect on amylase production. A 4.09-fold increase in production of α-amylase from B. licheniformis was achieved using RSM as compared to One Factor At a Time. The enzyme was purified by using Diethylaminoethyl Cellulose column chromatography and subsequently by Sephadex G-75 gel filtration chromatography. Result: A purification fold of 23.39 and a yield of 12.12% was observed. A single band of 33 kDa was obtained using Sodium Dodecyl Sulphate (SDS) and native-Poly Acrylamide Gel Electrophoresis (PAGE) which indicated that the enzyme was purified to homogeneity and was a monomer. The enzyme showed stability at 50 and 65°C temperatures and at alkaline pH. Conclusion: The stability of purified enzyme at high temperatures and alkaline pH suggested its wide application in textile, detergent and paper industries. Keywords: Amylase; Bacillus licheniformis; RSM; SDS-PAGE; alkaliphilic; thermostable enzymes

No abstract