Fermented rice extract as a carbon source for biomass production of aquaculture probiotics

Traditional commercial media are costly and not ideal for large-scale probiotic production in aquaculture. Choosing the right carbon source for probiotic growth and understanding how biomass production works can offer valuable insights for potential use in aquaculture. In this study, we tested 12 starchy extracts as potential cost-effective alternatives to supplement the culture media for the production of biofloc-based probiotic isolates. We cultured probiotic strains obtained from shrimp biofloc farms and assessed their growth density and cell viability. We isolated and identified probiotic strains that were likely to be Lactobacillus sp., Bacillus sp., Pseudomonas sp., and Saccharomyces sp. Of all the starchy extracts tested, the fermented rice extract proved to be an effective carbon source for boosting cell density, viability, and metabolic activity. We also experimented with fermented rice extracts in a lab-scale bioreactor for biomass production of these isolates. In this experiment, all the strains showed an increase in cell density over time. Pseudomonas sp. exhibited the fastest growth rate, followed by Saccharomyces sp., Lactobacillus sp., and Bacillus sp. The results of this study revealed that newly formulated culture medium not only reduced production costs but also boosted biomass production and cell viability of these isolates. This straightforward and practical process improves the biomass yield and probiotic effectiveness, which could potentially benefit the aquaculture industry.