Isolation and characterization of Arctic microorganisms decomposing bioplastics

Aneta K Urbanek,Łukasz Franczak,Mateusz C Strzelecki,Aleksandra M Mirończuk,Waldemar Rymowicz,Waldemar Kociuba

doi:10.1186/s13568-017-0448-4

Abstract

The increasing amount of plastic waste causes significant environmental pollution. In this study, screening of Arctic microorganisms which are able to degrade bioplastics was performed. In total, 313 microorganisms were isolated from 52 soil samples from the Arctic region (Spitsbergen). Among the isolated microorganisms, 121 (38.66%) showed biodegradation activity. The ability of clear zone formation on emulsified poly(butylene succinate-co-adipate) (PBSA) was observed for 116 microorganisms (95.87%), on poly(butylene succinate) (PBS) for 73 microorganisms (60.33%), and on poly(ɛ-caprolactone) (PCL) for 102 microorganisms (84.3%). Moreover, the growth of microorganisms on poly(lactic acid) (PLA) agar plates was observed for 56 microorganisms (46.28%). Based on the 16S rRNA sequence, 10 bacterial strains which showed the highest ability for biodegradation were identified as species belonging to Pseudomonas sp. and Rhodococcus sp. The isolated fungal strains were tested for polycaprolactone films and commercial corn and potato starch bags degradation under laboratory conditions. Strains 16G (based on the analysis of a partial 18S rRNA sequence, identified as Clonostachys rosea) and 16H (identified as Trichoderma sp.) showed the highest capability for biodegradation. A particularly high capability for biodegradation was observed for the strain Clonostachys rosea, which showed 100% degradation of starch films and 52.91% degradation of PCL films in a 30-day shake flask experiment. The main advantage of the microorganisms isolated from Arctic environment is the ability to grow at low temperature and efficient biodegradation under this condition. The data suggest that C. rosea can be used in natural and laboratory conditions for degradations of bioplastics.

Highlights

Three hundred and eleven tons of plastic were produced in 2014 (PlasticsEurope 2015)
We focused on the Arctic environment to isolate microorganisms which are able to rapidly decompose bioplastics at low temperatures
We focused on the Arctic environment to isolate microorganisms which are able to rapidly decompose bioplastics at low temperatures, what can reduce electric energy usage in biodegradation process in laboratory conditions

Summary

Introduction

Three hundred and eleven tons of plastic were produced in 2014 (PlasticsEurope 2015). This enormous number suggest that plastic has many applications in our daily life and industries (Uchida et al 2000), mainly in packaging, building and construction, automotive, agriculture, electrical and electronic (PlasticsEurope 2015). Plastic materials have some disadvantages, the most important criterion is its long long-term persistence in the environment in consequence of their resistance to degradation (Gajendiran et al 2016). Extensive use of polymeric materials have made plastic pollution. The continuously growing global production of plastic has a big Urbanek et al AMB Expr (2017) 7:148 influence for this virgin territory. The plastic ingestion has been documented in over 100 species of seabird (Trevail et al 2015)

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