Effect of Bacillus tequilensis SALBT crude extract with pectinase activity on demucilation of coffee beans and juice clarification.

Abstract

Pectinases are a group of enzymes, which catalyzethe breakdown of pectin with numerous applications in various industries. Microbes are the predominant pectinase producers. In the present study, bacterial species were isolated from the soil of a vegetable and fruit dumpyard area in a market. The species screened and isolated were identified as Bacillus tequilensis SALBT, and the media and culture conditions were optimized for enhanced production of total pectinases.Maximum pectinolytic activity was observed with 1.5% (w/v) pectin concentration with a combination of yeast extract as nitrogen source and MgSO4 as a metal ion source. Carbon/nitrogen in 2:1 ratio (w/v) yielded the maximum pectinase production with pH and temperature of the medium of 7.5°C and 40°C, respectively. Pectinase activity was determined by the dinitrosalicylic acid method. The pectinase production was relatively stable in the presence of various surfactants like Tween (20, 40, 60, and 80) and sodium dodecyl sulfate (SDS), whereas Triton X-100 showed an inhibitory effect. Mass production of the enzyme in optimized media and partial purification was performed by ammonium sulfate precipitation followed by dialysis. The approximate molecular weight of the partially purified pectinase was found to be 35 kDa by SDS-polyacrylamide gel electrophoresis. Application studies such as demucilaging coffee beans and juice clarification were also performed. The findings revealed that B. tequilensis SALBT with pectinase activity has the ability to remove the mucilage layer of pulped coffee seeds, and the partially purified pectinases found to be effective in clarifying juice.