Degradation of various types of plastic by strains of the Bacillus genus

Plastic is one of the largest sources of environmental pollution. A number of techniques have been used to reduce pollution [1,2]. Biodegradation is an environmentally friendly technique in which microorganisms are used to degrade various substances [3]. In this work, the ability of bacteria of the genus Bacillus to produce enzymes involved in the degradation of plastics and their potential to degrade plastic substrates were investigated. The substrates were: tributyrin, coconut oil, polycaprolactone diol (PCLD), terephthalic acid (TPA), bis(2-hydroxyethyl) terephthalate (BHET), polycaprolactone (PCL), impranil, polyethylene terephthalate (PET), polyhydroxybutyrate (PHB), linear low density polyethylene (LLDPE) and polypropylene (PP). The microbial enzyme production assay was performed on LuriaBertani (LB) agar with 3 % substrate, and degradation screening was performed on mineral (MSM) agar (2 % substrate). The tested microorganisms, isolated from the environment polluted with mixed plastic vaste, produced numerous enzymes and efficiently degraded a large number of different plastic substrates. Specifically, microorganisms did not grow on petri dishes with TPA. The best growth was shown by strains B. firmus, B. licheniformis and B. aryabhattai, while two B. ciccensis strains did not grow on coconut oil, PCL, Impranil, PHB and BHET. The study contributes to bioremediation processes and the discovery of new strains that can be used in biodegradation processes.