Exploring two-stage fermentation strategy of polyhydroxyalkanoate production using Aeromonas hydrophila

• Propose optimal mode of fermentation operation for PHA production.
• Unveil two-stage operation strategy for treatment and materials recycling.
• Disclose optimal nutrient-limiting conditions for PHA accumulation.

With consideration of sustainable development, this study explored the fermentation strategy of cost-effective production of biodegradable polymer- polyhydroxyalanoates (PHAs) for feasibility of eco-friendly materials recycling during wastewater treatment. As prior studies showed that Aeromonas hydrophila NIU01 was a promising PHA-producing bacterium, this follow-up study tended to seek for optimal nutrient-supplementation strategy to stimulate maximal PHA accumulation of A. hydrophila NIU01 for cellular production. As maximal PHA production took place at growth-limiting conditions, two-stage fermentation was much more appropriate for practical applications compared to batch mode of operation. Moreover, this optimal two-stage operation strategy maximized cellular PHA production under nitrogen-limiting conditions at C/N molar ratio of 60/1. For materials recycling, this operation strategy could be applicable to simultaneous PHB production and wastewater decolorization using A. hydrophila.