Study On Direct Production Of Fumaric Acid From Tapioca Flour By Rhizopus Arrhizus

Fumaric acid is also named fumarate and its chemical name istrans-1,2-ethylenedicarboxylic acid. Fumaric acid is a four-carbon unsaturateddicarboxylic acid that is widely used in the fields of medicine,food, chemicals, resins, et c. In this paper, a strain of Rhizopus arrhizus as theoriginal strain saved in our lab was rejuvenated through bromocresol greenand propylene alcohol methods screening approach. One strain namedRhizopus arrhizus RH-7-13was selected as a excellent strain. The presentinvestigation deals with the direct production of fumaric acid from tapiocaflour without saccharification by a strain of Rhizopus arrhizus RH-7-13thathas an ability of saccharification of starch. Using a self-made air-lift reactor,42.32g/L fumaric acid was obtained.A optimal seed culture medium, the strain grew into the pellet, wasobtained through an orthogonal test. The optimal seed culture conditionsconsisting of: urea,1.5g/L; initial pH,2.5. The preculture was inoculated witha concentration of6.2×10⁷spores/mL.Because of degradation,fumaric acid production of original strain wasless than20g/L.39.63g/L fumaric acid production was obtained by a rejuvenated strain named Rhizopus arrhizus RH-7-13.Cassava is one of the world's three major tubers and was widely grown inChina's Guangxi region. Rhizopus arrhizus has a high ability ofsaccharification, which is used as koji in brewing industry. The presentinvestigation deals with the direct production of fumaric acid from tapiocaflour by a strain of Rhizopus arrhizus RH-7-13saved in our laboratory. Onefactor at-a-time method was employed for the optimization of tapioca flouramount and nitrogen source. The Plackett-Burman design was applied toevaluate the effects of six different nutrients,in which both tapioca flouramount and K₂HPO₄amount were found to significantly influence on thefumaric acid production. The amount of the two nutrients were optimizedsubsequently using response surface methodology. The optimal nutrients ofthe fermentaiton medium was: tapioca flour,84.14g/L; K2HPO₄,1.55g/L; urea,0.05g/L;ZnSO₄·7H₂O,0.025g/L; MgSO₄·7H₂O,0.5g/L; FeSO₄,5.0×10^-4g/L.The effects of tapioca flour fineness, liquid volume, inoculum concentrations,the calcium carbonate amount, in flasks on fumaric acid prodution fromtapioca flour by Rhizopus arrhizus was investigated. A maximum fumaric acidproduction of46.36g/L was obtained in flasks with a productivity of0.32g/L/h.Rhizopus arrhizus has a lush mycelium, and is easy to wrap stirringagitator in stirred tank reactor. Using a self-made2.5L air-lift reactor(culturetemperature30°C, aeration rate1.54vvm, the filling volume1.3L/2.5L),the fumaric acid production was up to42.32g/L, with a productivity of0.29g/L/h,which is high in the international.Using glucose as carbon source, Rhizopus arrhizus was adsorptedon cotton balls and loofahs, and the maximum fumaric acid productionwere up to29.33g/L and38.94g/L respectively.