Abstract
The study was sought to enhance the synthesis of thermal stable beta-cyclodextrin glycosyltransferase (beta-CGTase) using potato wastewater as a low-cost medium and assess the degree to which it is efficient for industrial production of beta-cyclodextrin (beta-CD) from raw potato starch. Thermophilic bacteria producing beta-CGTase was isolated from Saudi Arabia and the promising strain was identified as Bacillus licheniformis using phylogenetic analysis of the 16S rRNA gene. Alginate-encapsulated cultures exhibited twice-fold of beta-CGTase production more than free cells. Scanning electron microscopy (SEM) of polymeric capsules indicated the potential for a longer shelf-life, which promotes the restoration of activity in bacterial cells across semi-continuous fermentation of beta-CGTase production for 252 h. The optimal conditions for beta-CGTase synthesis using potato wastewater medium were at 36 h, pH of 8.0, and 50 degrees C with 0.4% potato starch and 0.6% yeast extract as carbon and nitrogen sources, respectively. The purified enzyme showed a specific activity of 63.90 U/mg with a molecular weight of similar to 84.6 kDa as determined by SDS-PAGE analysis. The high enzyme activity was observed up to 60 degrees C, and complete stability was achieved at 75 degrees C. High levels of activity and stability were shown at pH 8.0, and the pH range from 7.0-10.0, respectively. The enzyme has an appreciable affinity for raw potato starch with a Km of 5.7 x 10(-6) M and a Vmax of 87.71 mu moL/mL/min. beta-CD production was effective against 25 U/g of raw potato starch. The outcomes demonstrated its feasibility to develop a fermentation process by integrating the cost-effective production of beta-CGTase having distinctive properties for beta-CD production with ecofriendly utilization of potato wastewater.