Study On The Production Of Fumaric Acid By Biotransformation Of Food Waste Using Rhizopus Arrhizus

With the increase in average living standards,the annual production of food waste in China has reached 90 million tons.Food waste has high organic matter content,high water content,and abundant nutrients.It can be used as a carbon source and a nitrogen source for the production of organic matter by microbial growth and metabolism.However,it will bring hidden dangers to the environment and human health if it cannot be dealt with in time,because it is very easy to be degraded.Therefore,the utilization of food waste has become a key issue that people need to solve.Based on the fact that food waste is used as a source of nutrients for growth and metabolism of Rhizopus arrhizus through bio-fermentation.This study makes use of the simple conditions for growth of Rhizopus arrhizus and the characteristics that TCA cycle in vivo can accumulate fumaric acid,to achieve the production of fumaric acid and the goal of degrading food waste.1.In order to optimize the morphology of Rhizopus arrhizus in the food waste and increase the yield of fumaric acid,the seed medium conditions were optimized,according to the fact that Rhizopus arrhizu is a non-growth coupled strain.The results showed that the yield of fumaric acid was 15.55 g/L after optimization of the main components of the seed medium,which was 37.85%higher than the optimized(11.28 g/L)and the space-time yield was 162.00 mg/(L·h).In addition,the homogeneity and compactness of strains were improved compared to those before optimization.And the diameter of the bacterial balls after fermentation was 5 mm.Changes in these phenomena all contribute to the production of fumaric acid.2.In order to improve the ability of strains to adapt the fermented liquid of food waste,the bacteria strains were selected through the methods of pressure screening and mutagenesis of food waste,and the degradation rate of food waste after fermentation was determined.It was found that the highest yield of fumaric acid was stabilized at 19.72 g/L in strains obtained after pressure screening,which was 26.82%higher than the yield of fumaric acid fermented by the initial strain(15.55 g/L).After the mutagenesis screening,the yield of fumaric acid was stable at 23.94 g/L,which was nearly 53.95%higher than that of the original strain,and the space-time yield was 249.38 mg/(L·h).3.Rhizopus arrhizus used the kitchen waste to ferment and obtain the product.At the same time,the use of nutrients also achieved the purpose of degradation of food waste.The degradation rate of the food waste after fermentation was measured.It can be found that the COD value of restaurant waste was reduced from the initial 133558.65 mg/L to 4926.28 mg/L,and the degradation rate was as high as 96.31%.4.To optimize the shake flask fermentation process for the purpose of enrichment of fumaric acid.The results showed that when the yield of fumaric acid reached the highest point in the fermentation process,the fermentation broth enriched in fumaric acid was poured out and replaced with fresh fermentation broth to continue fermentation,and the displaced fermentation broth was used for the extraction and extraction of fumaric acid.This method is feasible.