Identification,Culture Of The Fungus A-01and Preliminary Study On The Fermentation Products

Nowadays, the natural pigment obtained by microbial fermentation, for its rich resource, safety,no pollution to the environment and sustainable development are widely used. The tested strains were isolated from soil which have been identified, its fermentation conditions and the stability of product were studied,the results are as follows:1.An identification of morphological and molecular biology methods, to produce an acid-base indicator fungus were identified. The results showed that the strain asexual state Fusarium is Fusarium Moniliforme, about12hours after inoculation, the spore cell begin to initiate, were papillary or pyramidal, its shape fine and coarse. Small conidia sub-chain with raw or slimy heads.Homology analysis by PCR amplification and sequencing of the rDNA ITS of the strains, with the NCBI website, the results show that the homology of the test strains and Fujikura Fusarium, is100%,determine the strain is Fujikura Fusarium.2.In order to improve the production of pigment, the A-01strain culture conditions are optimized. OD485nm value indicators pigment under ultraviolet spectrophotometry, filter out the best culture conditions for the solid culture is PDA, the best liquid medium is potato dextrose medium, the best carbon source is sucrose, the best nitrogen source is fishmeal, the optimum temperature is28℃, the optimum pH value is6.5, the optimum fermentation time is120h, the optimum fermentation speed is180r/min, the optimum liquid volume is75mL/250mL.In order to obtain the best ratio,the four factors of carbon source concentration, nitrogen source concentration, temperature, pH value of the orthogonal experiment, in which the greatest impact on the production of pigment is temperature, followed in turn:carbon source, pH and nitrogen source.The orthogonal experiment results show that the best ratio is:fermentation temperature28°C, initial pH6.5,2.5%sucrose,2.5%fishmeal.3.A-01fermentation product stability experiment results show that the thermal stability of fermentation product is stable, however, as the temperature rises, the stability of pigment is weaker. In neutral pH conditions, the stability of the pigment is more stable, the pigment is not stable in acid and alkali conditions. The stability of the pigment under UV has almost no effect, indicating the pigment does not decompose by UV. Sunlight radiation does not affect the stability of the pigment. Na+and Fe3+damage the stability of pigment,K+and Mg+greatly damage the stability of pigment, but not produce more damage with the extension of time. Ca2+has no effect on the stability of pigment, can play a role of the stability of pigment. Citric acid has no effect on the stability of pigment, sodium benzoate has effect on the stability of pigment, but not produce more damage with the extension of time; sucrose and glucose do not damage the stability of pigment, On the contrary, there is a certain hyperchromic effect and is not affected with the extension of time.