Production Of Fumaric Acid From Food Waste By Rhizopus Arrhizus

Food waste (FW) rich in carbohydrates and protein are potential feedstock for production of renewable bio-based chemicals. From the data of the composition of food waste in four Seasons and three meals indicating that the value of VS/TS remained in a stable range are more than80%, The amount of four organic component (starch, protein, fat, cellulose) took up more than70%, among them the starch took up more than40%-50%, the fat and protein took up more than10%-15%.The results also showed the food waste (FW) contained some minerals such as magnesium, potassium, and calcium, which is important because the mineral ions are required elements for growth and metabolism of the R. oryzae strain. Nowadays, the treatments of food waste were landfill, incineration and compost, etc. The disposal of food waste has caused severe environmental pollution in many countries due to the increasing discharge of food waste. Therefore, it is imperative to overcome the technological and environmental of the conventional recycling method for food waste and simultaneously develop an environment friendly recycling method that can convert food waste to a high value product such as fumaric acid.Fumaric acid is a four-carbon unsaturated dicarboxylic acid that is widely used food industry, chemical industry and polymers industry. The Rhizopus arrhizus has been shown to be one of the most productive microorganisms in regard to fumaric acid production. This research investigated the capability of Rhizopus arrhizusRH7-13for the production of fumaric acid from food waste (FW). As the concentration of nitrogen sources was too high in fermentation medium containing FW, fumaric acid production by Rhizopus arrhizus RH7-13was limited while the mycelia grew well. The food waste is rich in nitrogen source and carbon source, while using it directly as the culture medium could only produce low fumaric concentration of13.26g/L and conversion rates was0.084g/g. While using100/L glucose common culture medium, the yield of fumaric acid could reach32.6g/L. And the60g/L FW combined with40g/LGlucose or80g/L Glucose was used to fermentation,25.3g/L and32.81g/L fumaric acid could be reached at the optimal conditions of50mL/250mLvolume load,20%inoclum size (v/v) and40g/L CaCO3,the conversion rates was0.25g/g and0.23g/g.Therefore, how to solve the high nitrogen presence in the food waste is an important challenge. The pretreatment of FW was heated at100℃for120min. The waste was then centrifuged at8000rpm for10min. After that, the food waste was separated into three parts:waste oil, solid portion of FW(S-FW), liquid portion of FW (L-FW).Using the L-FW as the fermentation medium, the concentration of fumaric acid could reach32.68g/L and conversion rates was0.236g/g at the optimal conditions of50mL/250mLvolume load, the Solid-liquid ratio of1:1,20%inoclum size (v/v) and40g/L CaCO3. On the other hand, when S-FW was used as the fermentation medium, the concentration of fumaric acid only reached13.23g/L. While60g/L S-FW combined with80g/L glucose was used for fermentation,31.26g/L fumaric acid could be reached and conversion rates was0.223at the optimal conditions of50mL/250mLvolume load,20%inoclum size (v/v) and40g/L CaCO3. And the60g/L FW combined with80g/L Glucose was used to fermentation,32.81g/L fumaric acid could be reached and conversion rates was0.23g/g at the same condition of fermentation. At the optimal conditions, the yield of fumaric acid from L-FW, S-FW have been improved about146.5%and135.7%compared with using food waste directly as the culture medium.Moreover, the fermentation broth from FW, L-FW and S-FW have high biomasses from42.31g/L to53.45g/L, After the fermentation process, the COD value of FW, S-FW and L-FW have been reduced by60.7%,66.3%,71%, the reduction of food waste were40%-60%. Efficient production of fumaric acid from food waste by Rhizopus arrhizus RH7-13can not only relieve the environmental pollution of food waste but also acquire an important biomass resource.