Poly(l-lactide)-Degrading Enzyme Production by Laceyella sacchari LP175 Under Solid State Fermentation Using Low Cost Agricultural Crops and Its Hydrolysis of Poly(l-lactide) Film

• Main Authors: Thanasak Lomthong, Rangrong Yoksan, Saisamorn Lumyong, Vichien Kitpreechavanich
• Format: Journal
• Published: 2020
• Subjects: Energy; Environmental Science
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85058859007&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/70524
• Institution: Chiang Mai University

© 2018, Springer Nature B.V. Purpose: The aim of this study was to investigate the enhancement of poly(l-lactide) (PLLA)-degrading enzyme production by Laceyella sacchari LP175 under solid state fermentation (SSF) using low-cost agricultural crops as substrates and its hydrolysis of poly(l-lactide) film. Methods: Cassava chip, soybean meal and corncob were used to investigate the enzyme production using a statistical mixture design method. The effect of various inducers and SSF growth conditions parameters affecting PLLA-degrading enzyme production were also investigated. The fermentation of solid substrates was up-scale in a static tray bioreactor. The crude enzyme extracted from the fermented solid substrate was used to evaluate the biological degradation of PLLA film at 50 °C for 24 h. Results: The results of substrate combination showed that 5 g of the substrate mixture, consisting of 4.3 g cassava chips and 0.7 g soybean meal, yielded 320 U/g dry solid. The addition of 0.1 g peptone to the mixture of solid materials increased enzyme production up to 456 U/g dry solid. The production of enzyme in a static tray bioreactor with optimized physical conditions yielded the maximum enzyme production, 472 U/g dry solid. The 20 mL reaction consisting of 8600 mg/L PLLA film was degraded by the crude enzyme extracted from the fermented solid substrate. Conclusions: Agricultural crops and wastes contain significant amounts of nutrients for microbial growth and products. This is the first reported of PLLA degrading enzyme production under SSF using low-cost substrates showing the possibility for application in large-scale biological recycling of bio-plastic as a future sustainable process.