Environmental biodegradation of haloarchaea-produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in activated sludge.
Novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) copolymers produced by haloarchaea are excellent candidate biomaterials. However, there is no report hitherto focusing on the biodegradation of PHBHV synthesized by haloarchaea. In this study, an environmental biodegradation of haloarchaea-produced PHBHV films, with 10~60 mol% 3-hydroxyvalerate (3HV) composition and different microchemical structures, was studied in nutrition-depleted activated sludge. The changes in mass, molar mass, chemical composition, thermal properties, and surface morphology were monitored. The mass and molar mass of each film decreased significantly, while the PHA monomer composition remained unchanged with time. Interestingly, the sample of random copolymer PHBHV-2 (R-PHBHV-2) (3HV, 30 mol%) had the lowest crystallinity and was degraded faster than R-PHBHV-3 containing the highest 3HV content or the higher-order copolymer PHBHV-1 (O-PHBHV-1) possessing the highest surface roughness. The order of biodegradation rate was in the opposite trend to the degree of crystallizability of the films. Meanwhile, thermal degradation temperature of most films decreased after biodegradation. Additionally, the surface erosion of films was confirmed by scanning electron microscopy. The dominant bacteria probably responsible for the degradation process were identified in the activated sludge. It was inferred that the degradation rate of haloarchaea-produced PHBHV films mainly depended on sample crystallinity, which was determined by monomer composition and microchemical structure and in turn strongly influenced surface morphology.
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.|University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Xiao-Bin
XB
Liu
Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|Guangzhou RiboBio Co., Ltd, Guangzhou, 510663, People's Republic of China.
Lin-Ping
LP
Wu
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Jing
J
Hou
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.|University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Jun-Yu
JY
Chen
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China. hanjing@im.ac.cn.
Jing
J
Han
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China. xiangh@im.ac.cn.
Hua
H
Xiang
D020155:3-Hydroxybutyric Acid / Q000378:metabolism*; D001105:Archaea / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D010421:Pentanoic Acids / Q000378:metabolism*; D010969:Plastics / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism; D011108:Polymers / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D000094122:Polyhydroxybutyrates
D020155:3-Hydroxybutyric Acid; D010421:Pentanoic Acids; D010969:Plastics; D011091:Polyesters; D011108:Polymers; D012722:Sewage; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates; C013056:beta-hydroxyvaleric acid
Bioerosion; Depolymerase; Environmental biodegradation; Haloarchaea; Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)