Plastic degradation by thermophilic Bacillus sp. BCBT21 isolated from composting agricultural residual in Vietnam

Three different kinds of plastic bags HL, VHL, and VN1 with different chemical nature were degraded by a novel thermophilic bacterial strain isolated from composting agricultural residual in Vietnam in shaking liquid medium at 55 o C after 30 days.  The new strain was classified in the Bacillus genus by morphological property and sequence of partial 16Sr RNA coding gene and named as Bacillus sp. BCBT21. This strain could produce extracellular hydrolase enzymes including lipase, CMCase, xylanase, chitinase, and protease with different level of activity in the same media. After a 30-day treatment at 55 o C, all characteristics including properties and morphology of treated plastic bags had been significantly changed. The weight loss, structure and surface morphology of these bags were detected, especially the average molecular weight of VHL bag was reduced 44.04%. New metabolites from the treated bags indicated biodegradation occurring with the different pathways. This finding suggests that there is high potential to develop an effective integrated method for plastic bags degradation by a combination of extracellular enzymes from bacteria and fungi existing in the composting process.