Direct Fermentation Of Fishmeal Wastewater And Starch Wastewater To L-Lactic Acid By Rhizopus Oryzae

Fishmeal wastewater (FWW) and starch wastewater (SWW), without additional nutrients, were investigated for the direct lactic acid production using Rhizopus oryaze AS 3.254. The aim was to find out cheaper raw materials for lactic acid production as well as to reuse the food wastewater resources.The investigation firstly focused on the effect of concentration of FFW and starch, initial pH, fungal morphology on lactic acid production. Also, the medium component and levels of inoculum and CaCO₃ were investigated by employing the orthogonal design while the actual factors affecting the production of L-lactic acid were evaluated by ANOVA. The results indicate starch as carbon source was the primary influence factor on L-lactic acid production, followed by pH, fishmeal wastewater and inoculum. The optimal doses for starch, CaCO₃, fishmeal wastewater and inoculum level were 120 g/L, 20 g/L, 4000 mg COD/L and 3%, respectively.Based on the optimal fermentation medium, fishmeal wastewater and concentrated starch wastewater were directly fermented by Rhizopus oryzae AS 3.254 for L-Lactic acid production. The highest lactic acid production of 76.0 g/L was achieved with 5.3 g/L fungal biomass at fermentation time of 72 h while removal of COD reached around 95%. Nitrogen of wastewater had been removed 72.7% by Rhizopus oryzae AS 3.254 at fermentation time of 24 h.