TY - DATA T1 - Data underlying the research of Efficient Hydrothermal Pretreatment of Mixed PHA/PLA and Consequent Continuous Anaerobic Fermentation into VFA PY - 2025/07/18 AU - Yong Jin AU - Ralf Beckmans AU - Kasper D. de Leeuw AU - David Strik UR - DO - 10.4121/7b56b29c-eeac-4536-95d8-eb8927aba78c.v1 KW - biobased biodegradable plastics KW - hydrothermal processing KW - open-culture fermentation KW - chain elongation KW - microbial community analysis KW - mixed bioplastic conversion N2 -

Recycling biobased biodegradable plastics such as polyhydroxyalkanoates (PHA) and polylactic acid (PLA) is essential for developing a circular economy. This study presents an integrated strategy that combines batch hydrothermal processing at 150℃ with continuous open-culture fermentation to convert PHA and PLA into C2-C6 carboxylates. Co-hydrolysis in a carboxylic acid solution significantly enhanced PHA depolymerization compared to PHA hydrolysis alone. Among various catalytical supplements, PLA addition notably improved PHA hydrolysis, achieving up to 91% dissolution. Throughout fermentation, acetate and n-butyrate were the primary products. In Phase VI, co-fermentation of PHA hydrolysates (~10 g/L 3-hydroxybutyrate) and PLA hydrolysates (5 g/L lactate) yielded acetate (4.4 g/L), n-butyrate (8.0 g/L), and n-caproate (0.3 g/L), while also reducing the need for KOH for pH control. An overall conversion efficiency of 89% from bioplastics to carboxylates was achieved, with a high n-butyrate selectivity of 71%. Supplementing with ethanol (7 g/L) further enhanced chain elongation, increasing n-butyrate concentration to 10.1 g/L, although excess ethanol oxidation was observed. This study demonstrates, for the first time, the successful continuous open-culture fermentation of PHA and PLA hydrolysates into carboxylates. Microbial community analysis identified Clostridium tyrobutyricum as a key species likely responsible for dominant n-butyrate production.

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