2024 Volume 60 Issue 2 Pages 25-37
The production of polyhydroxyalkanoates (PHA) using waste activated sludge (WAS) as a biocatalyst is a promising strategy to achieve decarbonization and sustainability of wastewater treatment and enhance the economic viability of environmentally compatible bioplastic production. We recently established an aerobic dynamic discharge (ADD) process that can efficiently enrich PHA-accumulating bacteria, thereby reinforcing the PHA accumulation capability of WAS in only two days. Therefore, this study aimed to assess the general applicability of the 2－day ADD process using six WAS samples collected from different wastewater treatment plants. The results revealed that, irrespective of the seed WAS, the ADD process can enhance the PHA accumulation capability to achieve a 40 wt% PHA content, which is a key threshold for viable commercial PHA production using WAS as the biocatalyst. Microbial community analysis also revealed that, although noticeable changes in the overall microbial community structure and the dominance of specific PHA-accumulating bacteria did not occur through short-term enrichment, several PHA-accumulating bacteria among the diverse array of bacteria inherent in WAS increased to some extent, which ultimately contributed to enhancing the PHA-accumulating capacity. The overall results indicate the versatility of the 2－day ADD process for converting WAS into a biocatalyst for PHA production.
