Bacillus spp. enzymatic activity to support circular economy

Abstract

Agricultural and industrial waste represents the most abundant renewable resource in the biosphere and is readily available in substantial quantities. Recently, there has been a growing focus on harnessing the potential of these types of waste as raw materials for producing value-added products, such as microbial enzymes, using solid-state or submerged fermentation systems. Among all the bacterial genera utilized in the production of industrially important enzymes, the Bacillus genus stands out as the most extensively employed for this purpose. In this study, the production of various enzymes such as protease, pectinase, cellulase, xylanase, lipase, and gelatinase was evaluated using the different Bacillus strains isolated from vegetables? rhizosphere. The growth zones and halos were observed to determine production of the following enzymes: cellulases, proteases, pectinases, xylanases, gelatinases and lipases, confirming the breakdown of complex substrates in the medium. Bacillus Pap 3 exhibited the highest EAI (enzymatic activity index) value (4.00) for pectinase activity, indicating its remarkable extracellular level of pectinase performance. The highest enzymatic activity in terms of halo zone diameters was achieved in the case of cellulases and xylanases production by the isolates Mah 1a and Mah 1b. Further research would be directed towards the production of the tested enzymes by Bacillus spp. on the waste streams of food and agroindustry, but also towards the utilization of the proven enzymatic activity to obtain other microbial value-added products to develop viable bioprocess solutions usable in the circular economy context.