Studies On Mutation And Effects Of Physico-chemical Properties Of Aspergillus Oryzae Under High Pressure

In this paper, Aspergillus Oryzae 3.042 was treated by high pressureat the pressure of 0.1-400MPa within 20 mins. Studied effects of highpressure on death radio, modality, physico-chemical properties, proteaseactivity, amylase activity of Aspergillus Oryzae. And an excellent strainwas induced and screened by high pressure. The result showed that: HighPressure obviously influence the death radio and modality of AspergillusOryzae. The effects of high pressure on protease activity and amylaseactivity of Aspergillus Oryzae manifest especial disciplinarian which isthat protease activity decrease with the increase of pressure at the boundof 0.1-200MPa, however, it boost up with increase of pressure above 200MPato 400MPa. The protease activity of Aspergillus Oryzae the pressure of300MPa is larger than Aspergillus Oryzae without pressure treated.Protease activity is maximum at the pressure of 400MPa. Amylase activitydecrease at the pressure of 100MPa, is the strongest at 200MPa, while itdecrease when pressure increase above 200MPa. The amylase activity ofAspergillus Oryzae at the pressure of 400MPa is same as Aspergillus Oryzaewithout pressure treated. In addition, a perfect variation strain HP300awas screened at the pressure of 300MPa which has quick growth, more spores,higher protease activity, and is rarely polluted by other strains. Severalmain indexes of soy sauce koji of HP300a are all better than AspergillusOryzae without pressure treated, and some main indexes of soy sauce arealso better than strain without pressure treated. The original strainAspergillus Oryzae 3.024 and high pressure induced strain HP 300a subjectedRAPD(random amplified polymorphic DNA) and ISSR(inter simple sepuencerepeats) analysis.Results showed distinct polymorphic ,84.44% and 73.22%respectively. ISSR analysis indicated that the mean absolute distancecoefficient between the original cultivar and the Mutant 1 is 0.553.RAPDanalysis demonstrated that the mean absolute distance coefficient betweenthe original cultivar and the Mutant 1 is 0.750. Results indicated thatit is possible to obtain stable Aspergillus Oryzae mutants, include bothgenetic and epigenetic changes, by high pressure treatment. It providedtheoretic evidences to high-pressure induced Aspergillus Oryzae mutants.High pressure seems an efficient approach for mutagenesis.