Aspergillus Niger In The Degumming Of Hemp And The Research Of Its Mutagenesis

Hemp taxtiles have good antibacterial ability,functions of moisture permeabil-ity and shielding radiation,being the real "green product".However,hemp textile processing technology was not mature enough.Comparing with chemical degumming, bio-degumming technology has good prospects and great advantages in the quality of hemp fibre,energy cost and environmental preservation.The current technical difficulty is how to reduce residual gum and lignin content furtherly after degumming. The results show that the strain capble of producing high pectinase can reduce the residual gum content,but the hemp fibre can not meet the demand. So,chemical degumming process needs to be used to improve the degumming results.The experiment activated strains of Aspergillus niger,which was preserved in the chamber of spawn preservation,college of life science in Shandong University,only to get eight stains of Aspergillus niger that grow rapidly and healthily without any contamination. The crude enzyme solution of the liquid fermentation of Aspergillus niger2is determined the activity of enzymes,which showed the it had high activity of pectinase and xylanase,low activity of cellulose.So, Aspergillus niger2can meet the demand of textiles and be used in the degumming of hemp.Hemp fibre has lignin and Aspergillus niger2has none enzyme that can eliminate lignin,for which we used laccase in the degumming.Through the experiment of degumming and laccase,we can get that the activity of the laccase which was determined quantatively was3.72×104U/g. Aspergillus niger together with laccase showed that the experiment group having laccase increased weight loss rate by4.27%,decreased residual gum content by2.94%and lignin content by1.73%.Through the experiment of chemical degumming,the test team using laccase decreased residual gum content by1.1%and lignin content by2.04%.We made orthogonal experiment of five factors including laccase and four chemical reagents,and four levels only to get desired effect of eliminating gum and to use chemical reagent as little as possible.After completing the orthogonal experiment,we got the optimal result:laccase3.5mg/mL, NaOH5.0%, NaSiO32.5%, Na3PO41.0%, Na2SO31.6%.We decreased the quantity of NaOH1.0%, NaSiO30.5%and Na2SO30.4%..Then,we mutagenized Aspergillus niger by ultraviolet,ARTP plasma system and together with each other.Finally,we got an optimal strain:C36-2.After culturing,we got crude enzyme solution fermentation liquid and determined the activity of cellulase,xylanase and pectinase.Compared with the starting strain,made the activity of pectinase improve5.97%,the activity of xylanase improve2.56%and the activity of cellulose decrease3.15%.In the process of solid fermentation,the activity of pectinase and xylanase got to7283.1and5628.7enzyme activity unit.Meanwhile,the activity of cellulose got to1954.4enzyme activity unit.