The Research On Aspergillus Niger Degradation Potato Cellulose Effect Strengthening

Potato pulp and juice are rich in a lot of cellulose, hemicellulose, amino acids,vitamins, protein, pectin, trace elements. With the vigorous development of starch,more than one thousand potato starch factories each year produce and let out morethan a few hundred tons of potato residue and juice, due to the lack of scientific andeffective techniques, resulting in potato residue and juice can not be effectively dealtwith, large number of nutrients losing at the same time also a heavy burden on theenvironment. Cellulose degrading bacterias can utilize cellulose by fermentationmethod to produce a variety of high value-added products such as single-cell proteinand fertilizers.In this experiment, laboratory preserved strains Aspergillus niger as the startingstrain of by UV and ethylmethylsulfone compound mutation, the purpose is toobtain high yield and genetic stability of cellulase good mutants, effectively degradepotato slag cellulose, cellulose degradation rate increased while better solutionpotato juice residue and the environmental problems.Best ultraviolet irradiation time30min, ethylmethylsulfone optimal treatmenttime was60min. Congo red staining by screening, CMC activity rescreening, fivetimes after subculture get a good cellulase producing strains H3. Liquidfermentation under the same conditions, the CMC of the original strain and FPenzyme activity were1.18U and0.62U; H3, CMC mutant enzyme activity and FPwere5.83U and2.23U, were increased by4.9-fold and3.6-fold than the originalstrain.In order to obtain high activity of mutant H3from the temperature, pH,fermentation time, nitrogen, carbon, inoculation six aspects of optimization offermentation conditions. H3strains best fermentation temperature is40°C, pH6,fermentation cycle4d, optimum inoculum1%, the best nitrogen source (NH4)2SO4,best carbon bran; strains CMC enzyme activity was determined as8.86U; FPactivity of4.79U. Before optimization were increased1.5-fold and2.1-fold.Original strain and mutant strains H3under the same conditions, respectively,semi-solid medium fermented potato4d, H3strains was determined on potatodegradation rate of80.54%of cellulose, original strain of potato cellulosedegradation was39.25%, improved2.05times.Experiments show that mutant H3has a good cellulase production capacity tofurther enhance the degradation rate of potato cellulose. The use of UV and EMS mutagen has achieved good mutagenesis results, strengthened the cellulaseproduction capacity of Aspergillus niger.