Study On Using Food Waste To Produce Lactic Acid And Fumaric Acid

The food waste is catering waste which is generated by people intheir daily lives and some discarded food materials after the cookingprocess; it has big water content, and is highly perishable, makesunsavory smell to attract mosquitoes, so it finally results in a series ofenvironmental and healthy issues. With the rapid economic developmentand people's standard of living, output of food waste increases fast. Insome large cities, production of food waste by one person has reached1kg/d. In the face of such a large food waste generation, seeking asimple, environmentally friendly, effective treatment approaches isbecoming the focus of people's research. Because some characteristics offood waste are not suitable for traditional waste disposal methods, sosome approaches are emerging, such as fermentation of methane,hydrogen production, fermentation production of lactic acid. Therefore,two directions were selected by us: some preliminary research on usingfood waste fermentation to produce lactic acid and fumaric acid werecarried out, the details and results were included next: (1) Food waste of cafeteria in Beijing University of Chemicaltechnology were chosen as raw material, and made determination ofcomposition of the three meals in a day and food waste all year round tofind changes. Results showed that food waste composition in the FourSeasons and three meals did not show regular changes, but value ofVS/TS remained in a stable range, were more than88%, five organiccomponent content in total took up more than70%, so we could find thatfood waste had a strong potential for biodegradable, and it is an idealraw materials for fermentation.(2) From food waste, a strain which was able to use starch toproduce lactic acid was successfully screened, and after furtherphysiological, biochemical test and16s rDNA of identification, thestrain of LL-6was determined as Streptococcus equinus. Then the strainof LL-6was used to produce lactic acid by open fermentation and closedfermentation of food waste, the highest output of lactic acid could reach29g/L and26g/L respectively, and productivity was0.36(g/g dry waste)and0.33(g/g dry waste). The output of lactic acid production increasedby20.83%and9.8%more than yield of non-inoculated fermentation offood waste respectively.Strain Lactobacillus rhamnosus which was saved in the lab wasadopted in open fermentation and simultaneous saccharification to usefood waste to produce lactic acid, the highest lactic acid production could reach32g/L and38g/L, and productivity were0.41(g/g dry waste)and0.47(g/g dry waste). The output of lactic acid production increasedby33.33%and58.33%more than yield of non-inoculated fermentationof food waste respectively.(3) RH-0713which was saved in the lab was used to producefumaric acid, then by a single factor experiment, the effect of the foodwaste (wet weight) content, inoculums, calcium carbonate addition andthe liquid volume in the fermation of food waste to produce fumaric acidwas explored, and the optimum fermentation conditions for the use offood waste to produce fumaric acid was studied by orthogonalexperiment. Experimental results told: when food waste (wet weight)content was30g:50mL, inoculums was15%, calcium carbonate was4%,liquid volume was50mL, fumaric acid accumulation in the fermentationbroth could achieve12.47g/L, and fumaric acid conversion rate is0.12(g/g dry waste).