Screening of proteolytic, amylolytic, and lipolytic bacteria and their consortia for concomitant production of hydrolytic enzymes and bioremediation of shrimp pond sludge

Background

Aquaculture has become the fastest-growing sector in recent decades, and this has led to intensified cultural practices to achieve high yields. However, such practices have raised concerns regarding their environmental impact, as aquaculture sludge and wastewater cause significant organic pollution. This study then aimed to isolate and screen proteolytic, amylolytic, and lipolytic bacteria and evaluate their consortia for enzyme production and bioremediation of shrimp pond sludge.

Results

The strategy using multiple substrates in the isolation media successfully obtained bacterial strains with multiple hydrolytic activities. After primary and secondary quantitative screening, 18 isolates that exhibited high dual and triple hydrolytic activities were selected. After tertiary quantitative screening using synthetic shrimp pond sludge and co-culture tests, Exiguobacterium indicum SSP-PA-08, Bacillus coagulans, and Bacillus subtilis were selected due to their synergy for the production of triple hydrolytic enzymes. Their consortia inoculated in shrimp pond sludge containing 0.8% total suspended solids (TSSs) showed an increase in proteolytic activity by 2.5 folds and amylolytic activity by 20 folds, which led to a greater reduction in TSS. The highest enzyme production was obtained using shrimp pond sludge containing 1.6% TSS.

Conclusions

This study has developed the methods to isolate bacteria with multienzyme-producing ability. Co-culturing these bacteria in synthetic shrimp sludge significantly enhanced hydrolytic activity and led to a greater reduction in TSS. These strategies may contribute greatly to the hydrolytic enzyme production and environmentally friendly bioremediation of aquaculture sludge.

How to cite: Thongsongkaew C, Cheirsilp B, Billateh A, et al. Screening of proteolytic, amylolytic, and lipolytic bacteria and their consortia for concomitant production of hydrolytic enzymes and bioremediation of shrimp pond sludge. Electron J Biotechnol 2025;77. https://doi.org/10.1016/j.ejbt.2025.05.005.