Biodegradation of poly(tetramethylene succinate-co-tetramethylene adipate)and poly(tetramethylene succinate) through water-soluble products

Poly(tetramethylene succinate-co-tetramethylene adipate) (PBSA) and poly (t etramethylenesuccinate) (PBS) were hydrolyzed experimentally into water-sol uble oligomers and monomers by Chromobacterium extracellular lipase. The ol igomers were identified by high-performance liquid chromatography-mass spec trometry and IH-nuclear magnetic resonance, which indicated that a total of 28 oligomer species were liberated from PBSA, and that 13 of them were ide ntical to the hydrolysates from PBS. Moreover, 20 of the species were polye ster-based compounds of monomer units, and the other 8 species were small a mounts of diurethane compounds. Bis(hydroxybutyl) succinate (BSB) and bis(h ydroxybutyl) hexamethylene dicarbamate (BHB) were the typical oligomers and were chemically synthesized. Biodegradability of BSB and BHB was examined for 28 d in the activated sludge, and analysis of the results of this study indicated that the final conversion rate of constituent carbon to carbon d ioxide was estimated at 80 mol% for BSB and 10 mol% for BHB. The remaining amount of carbon in the undegraded BHB was 20 mot%. In the presence of BSB, the biodegradability of BHB was increased by about 1.5 times. The suggesti on was made that BSB induced a growth of microorganisms and helped BHB degr adation. This is consistent with the observation that the biodegradation of BHB in native soil for 60 d reached > 60%.