Isolation of A Nocardiopsis Chromatogenes Strain That Degrades PLA (Polylactic Acid) From Pig Waste–Based Compost

Abstract A new Nocardiopsis species that degrades polylactic acid (PLA) was isolated from pig dung–based compost from a municipal composting facility in Japan. To obtain strains capable of efficient PLA degradation, we minimized the effect of non-enzymatic degradation of PLA by maintaining the temperature at 37°C or below. After screening a total of 15 animal waste–based compost samples, consisting of pig dung, cow dung, horse dung, or chicken droppings, we found that compost derived from pig dung was most efficient for degradation of PLA film, and used it for isolation of PLA-degrading microorganisms. Screening for PLA-degrading microorganisms in compost was performed using an agar plate–based method; an emulsifier was omitted to avoid selection of strains that assimilated the emulsifier instead of PLA in the medium. After repeated enrichment, six strains were obtained. One strain that exhibited stable PLA degradation on agar plates was subjected to genomic analysis and identified as Nocardiopsis chromatogenes, an actinomycete.