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Bioplastics are eco-friendly and derived from renewable biomass sources. Innovation in recycling methods will tackle some of the critical issues facing the acceptance of bioplastics. Polylactic acid (PLA) is the commonly used and well-studied bioplastic that is presumed to be biodegradable. Considering their demand and use in near future, exploration for microbes capable of bioplastic degradation has high potential. Four PLA degrading strains were isolated and identified as Penicillium chrysogenum, Cladosporium sphaerospermum, Serratia marcescens and Rhodotorula mucilaginosa. A consortium of above strains degraded 44 % (w/w) PLA in 30 days time in laboratory conditions. Subsequently, the microbial consortium employed effectively for PLA composting.Keywords Biodegradability Á Polylactic acid Á Enzymatic degradation Á Microbial degradation As a result of rapid technology growth and global population explosion, the necessity of plastic materials enormously increased in every discipline of life and industries.The increasing accumulation of non-biodegradable synthetic plastics in the environment has been a menace to the earth. The bio-degradable nature of PLA makes it most acceptable to resolve this issue.A very few actinomycetes and thermophilic bacteria such as Brevibacillus, Bacillus smithii, Geobacillus, and Bacillus licheniformis has manifested PLA-degrading ability [1][2][3][4]. Jarerat et al. [5] reported that most of the degraders were restricted to the family Pseudonocardiaceae and related genera such as Saccharothrix, Amycolatopsis, Lentzea, Streptoalloteichus and Kibdelosporangium.PLA biodegradation takes place by the hydrolysis of the ester bonds. The ester linkages in PLA are vulnerable to both chemical hydrolysis and enzymatic cleavage. Microorganisms are devoid of transporters to uptake the plastic polymers directly into the cells due to water insolubility and size of the polymer molecules. The extracellular enzymes secreted by the microbes helps to depolymerize the polymer [6]. An interesting report was that enzymes like Proteinase K secreted by Tritirachium album can degrade PLA [7]. Lee et al. [8] proposed a mechanism of enzymatic degradation for PLA nonwovens fabrics and could be very useful for waste management in the textile industry. Earlier we reported that incorporation of relatively cheap and eco-friendly polymer such as thermoplastic starch, to PLA enhances its biodegradability [9]. The present work intends to demonstrate the rapid biodegradation of PLA by employing a consortium of few new microbial isolates.A commercial grade PLA with molecular weight of 85,000-160,000 was obtained from Sigma-Aldrich (India).Approximately 300 soil samples from different sources (Tropical rain forest areas of Western Ghats of Kerala, composting grounds in local markets, solid waste treatment plant, mangrove soil, activated sludges and dairy sludge Nimisha R. Nair and Vini C. Sekhar have contributed equally to this work. 123Indian J Microbiol (Jan-Mar 2016) 56(1):59-63 DOI 10.1007/s12088-015-0559-z...

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