Compost-derived thermophilic microorganisms producing glycoside hydrolase activities as new potential biocatalysts for sustainable processes

Abstract

Background: The management of the organic waste recycling process determines the interest in the thermophiles microorganisms involved in composting. Although many microbial enzymes have been isolated and studied for their industrial and commercial uses, there is still a continuous search for the potential microorganisms which could synthesize industrially feasible enzymes, especially when microbial diversity of cow dung makes itself a potential source of biotechnological enzymes. Results: The composting process studied at the Experimental Station of the University of Naples Federico II (Castel Volturno, Caserta, Italy) was characterized by saw dust 40%, bovine manure 58%, and 2% mature compost as raw organic substrates, and its thermophilic phase exceeded a temperature of 55 °C for at least 5 days, thus achieving sanitation. Five new microbial strains were isolated and named CV1-1, CV1-2, CV2-1, CV2-2, CV2-3 and CV2-4. Based on 16S rRNA gene sequence, HRMAS-NMR spectroscopy, and biochemical investigations, they were ascribed to the genera Geobacillus and Bacillus. The microbial isolates have been checked for the presence of glycoside hydrolase enzymes in extracellular, cell-bound, and cytosolic fractions. Moreover, pectinase activities have been researched. Conclusions: The isolation of new thermophilic microorganisms has allowed to study the compost biodiversity, and subsequently permitted the identification of enzymatic activities able to degrade cellulose and other polymeric substrates, which could be interesting from an industrial and a biotechnological point of view, furthermore, increasing knowledge and potential applicability in different industrial fields