Heavy Ion Irradiation Combined with Alpha-cellulose Adaptive Evolution to Improve Cellulase Activity of Aspergillus niger

In order to obtain high-yielding cellulase strains that can effectively degrade cellulose in plant cell walls, Aspergillus niger, which has the advantages of safety and reliability, non-toxicity, fast growth and short fermentation period, was used as the starting strain. The original strain, Aspergillus niger, was irradiated by heavy ion beam ¹²C⁶⁺ (irradiation doses: 40, 70, 100, 130, 160 and 190 Gy) , and two excellent strains were obtained after primary screening on the plate; 8 weeks of self-adaptive evolution, the strain has stable growth performance through 5 consecutive generations of fermentation; the obtained strains of each generation were compared for the molecular weight of intracellular proteins, and an optimal mutant strain CJH-JWSFZh-W122 was obtained, which was determined by shaking flask fermentation Cellulase activity, the filter paper activity(FPA) of cellulase production reached 223.5 U/mL, and the carboxymethyl cellulase activity(CMCase) reached 440.8 U/mL, which were 6.07% and 8.01% higher than the original strains, respectively. The excellent fermentation performance was still maintained after 5 consecutive generations; RAPD analysis and SDS-PAGE electrophoresis analysis were applied to compare the mutant strain CJH-JWSFZh-W122 and original strain, which confirmed the gene mutation of this strain.