The Research Of Microbial Agents For Pitch Troubles In The Process Of Papermaking

The strain Z75of the research have the ability of degradating the natural resins, which is collected from the soil sample of paper mill in Nanping.Through its morpHological observation.The strain Z75colony is big, weak gray, circular, the edge of colonies is smooth, its surface is wet; After oil mirror observation, we make preliminary analysis to identify strain Z75as short coli. After the16SrDNA appraisal and evolutionary tree analysis, the strain Z75belong to Enterobacter gergoviae, named: Enterobacter pulveris. Z75. But at the same time, through the data analysis evaluation of strain Z75in the process of degradating natural resins, setting the degradation reaction of the degradation rate for the substrate particle size to be0.200g, the most suitable degradation time is more than20h.The fermentation conditions and the culture medium of Enterobacter pulveris. Z75is optimized, through the single factor experiment, we determine the optimal carbon source for glucose, the optimum nitrogen source for yeast powder, initial fermentation pH7.7, the temperature for36℃, fermentation with fluid amount for40/250ml, and make preliminary sure for fermentation conditions and cultivate formula. Through the Plackett-Burman experimental design, reviewing eight factors of influencing strain Z75degradation ability of the natural resins strains to choose the biggest two factors for the degradation rates:yeast powder and initial pH. Through the steepest hill experiment, we find out the area which has the highest rate of degradation, in this region,we make Box-Behnken response surface design, and conclude that the yeast powder and initial pH value respectively is:3.85%and7.63. After the optimization, the degradation rate increased from6.5%to22.49%, and improve more than three times.The preliminary research of100L fermentation tank indicates that in the process of fermentation, the air flow is1:0.6(air flow V:pack fluid volume V), bubble enemy is choosed as defoaming agent and Addition amount is5‰. In addition, in the end of the fermentation judgment, we Put cans mainly after three hours when pH is8.6or according to color and stink judgment, or the growth curve at14h.The study of small amounts of enrichment method in the laboratory shows that dialysis bag whose molecular size is10000-12000has the best effect of the concentration,from the data of experiment from enrichmen,wo can see that the concentration effect increase with related enrichment multiples, at the same time, the molecular weight of degradation factors which exist in the microbiae’s fermented liquid which can degradate natural resins is about10000.From the Hollow fiber cutting inside the filter enrichment experiment, the results can be seen that hollow fiber cutting inside the filter enrichment experiment can achieve concentration ratio in a very short period of time, and degradation rate will greatly improve with the increase of concentration ratio, especially from the results of diluted experimental, the degradation rate of concentrated diluent and fermented liquid without the enrichment have little difference, so the concentration of fermented liquid has achieve the purpose of the enrichment.We test the effect of degradation test of natural resins with the uv-vis spectropHotometry, and draw that the previous evaluation methods which use weighing method to screen microbial are reliable, its credibility reached95%. At the same time,we make deinking experiment research on the fermented liquid of strain Z75, and concluded that it can not only effectively remove natural resin, but also can increase white degree of paper. The microbial agents for pitch troubles increase the market competitiveness in the process of applying, but also provide better returns for the application of waste paper.