An integrated approach for treatment and biomass resource recovery from juice industry wastewater using purple non-sulfur bacteria

This study aims to treat juice industry wastewater and recover resources using purple non-sulfur bacteria (PNSB). Simulated juice wastewater was prepared and used as a feedstock for PNSB. Carbon sources, including sucrose, fructose, glucose, and tris-Na-citrate, were added to different bottles separately and inoculated with a mixed culture of PNSB. Tris-Na-citrate showed higher growth and biomass production (650±70 mg/L) than the other carbon sources. The PNSB growth was associated with the pH change; tris-Na-citrate showed different pH change behavior than the other carbon sources, i.e., it showed a lesser decrease in the medium pH than the others. The effect of substrate (using glucose) concentration on PNSB biomass production was determined in the following experiment. A substrate concentration of 400 mg/L (as COD) showed the highest growth, whereas 800 mg/L (as COD) returned the highest biomass production (776±1 mg/L). Total organic carbon removal (TOC) increased with an increase in substrate concentration. Inorganic carbon removal initially decreased but then increased over the growth period; however, it was also directly correlated with initial substrate concentration. Lastly, the effect of pH on TOC, IC, and COD removal was investigated. A pH of 6.0 or above (up to 8.0) was required to remove organic and inorganic carbon.