Related Experiment Video
Updated: Jan 10, 2026

Scalable Step-by-Step Approach of Sustainable Bioplastic Production from Food Waste
Published on: July 18, 2025
Initiating the Caproate Production from Waste Activated Sludge without External Electron Donors by the Oriented
Jun-Yan Liu1, Kun Dai1, Qing-Song Lin1
1Center of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China.
None:
Medium-chain fatty acids (MCFA) are scarcely produced when waste activated sludge (WAS) is used as the sole substrate, limiting their practical development. Production typically requires external electron donors following chemical or physical pretreatments. This study demonstrates that an enriched MCFA-producing consortium (MPC) can initiate MCFA production from WAS without any external electron donors. In the WAS group, the COD conversion ratios from WAS to SCFA (short-chain fatty acids) and MCFA were 6.0% and 0%, respectively. After dosing MPC in WAS, these ratios increased to 20.7% and 4.6%, respectively. These results were attributed to the higher hydrolytic activity in MPC compared to WAS; for instance, the relative activity of alginate lyase in WAS was only 2.8% of that in MPC. Bacteroides (33.1%) was identified as the key bacterium in MPC due to its role in secreting multihydrolases and intracellular enzymes to degrade uronic acids. Conversion of the hydrolysates to MCFA occurred predominantly via the fatty acid biosynthesis (FAB) pathway, as evidenced by the comprehensive identification of FAB-related genes and active enzymes via multiomics analysis. The initiating mechanism is thus attributed to the high activity of both multihydrolases and the FAB pathway without external electron donors. Overall, this study demonstrates the oriented microbial method, coupling the hydrolytic efficiency of FAB-related bacteria and the favorable thermodynamics of the reverse β-oxidation (RBO) pathway in the future, to support the recovery of MCFA from WAS.
More Related Videos
15:19Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
11:58Waste Water Derived Electroactive Microbial Biofilms: Growth, Maintenance, and Basic Characterization
Published on: December 29, 2013
Related Concept Videos
Amino Acid Catabolism
Carbon-dioxide Fixation
Fates of Pyruvate
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...
Microbial Fermentation
Metabolism of Chemolithotrophs
Lipid Catabolism