(130e) Operational Factors Affecting Microalgae Cultivation in Oat Milk Wastewater

To build an independent and resilient food supply system, Singapore is exploring alternative sources, particularly those with low land requirements and high biomass conversion efficiency. Microalgae are often referred to as “sustainable biofactories” because they can be cultivated at an industrial scale and are rich in valuable nutrients including protein, polysaccharides, polyunsaturated fatty acids et al. Additionally, wastewater produced from food processing could be utilized as the algae culture media, which offers the dual benefit of reducing environmental burden and enhancing resource efficiency. In our previous study, we optimized the composition of the culture medium based on oat wastewater and observed that Chlorella sorokiniana can grow well during the flask batch culture process. Herein, this study was designed to evaluate the impact of key operational factors on the cultivation of microalgae in oat milk wastewater at a larger scale. We cultivated Chlorella sorokiniana in 2 L photobioreactors (PBR) with an extraneous supply of CO₂ using the adjusted oat milk wastewater as the culture medium and examined how the initial inoculum amount and the CO₂ flux influence the growth status and nutritional value. The growth kinetics were monitored through OD680nm and chlorophyll content measurements, the biomass productivity was assessed, and the nutrient profiles of the harvested biomass including protein, polysaccharides, and lipids were evaluated. The results showed that the initial inoculum amount directly affected the adaptation phase, growth rate, and biomass productivity of Chlorella sorokiniana. The CO₂ flux contributed to maintaining the optimal medium pH. Those findings demonstrate the feasibility of utilizing oat milk wastewater to establish single cell biorefineries for microalgae cultivation at a larger scale, and the analysis of nutrient profiles provides insight into potential applications of microalgal biomass in various food industries.