An accelerated biodegradation of Poly(lactic acid) by inoculation of Pseudomonas geniculate WS3 combined with nutrient addition

Abstract

This study aims to develop an efficient method for accelerating the biodegradation rate of Polylactic acid (PLA). A combined use of PLA-degrading bacterium, Pseudomonas geniculate WS3 and nitrogen source or enzyme inducer to accelerate biodegradation of PLA was proposed. PLA films were prepared and submerged in basal salt medium (BSM) amended with ammonium sulfate, soytone, sericin or sodium lactate and inoculated with P. geniculate WS3 for 30 days. The results showed that the highest percentage of PLA film-weight loss was found in the treatment of soytone addition, followed by sodium lactate addition. PLA films in culture broth with P. geniculate WS3 and soytone were cracked and broken down into small fragments within 20 days. In addition, increasing the lactic acid content as a monomer of PLA in culture broth was directly correlated with increasing the percentage of PLA film-weight loss. It could be concluded that a combined use of P. geniculate WS3 and soytone exhibited a high potential to significantly accelerate the PLA biodegradation under the submerged condition.