| Acetobacter is the common strains in production of vinegar and vinegar beverage. The biological characteristics determine the production and flavor of vinegar. Breeding of Acetobacter must maintain its excellent characters so that can be used in long-term production.At present, most of vinegar production factory use ordinary slant preservation, requiring periodic passage, easy to make the strain degeneration. Solid-state acetic acid bacteria used in production exists a lot of questions such as viable count and activity are not stable.Preservation conditions of liquid preservation are not clear. The main factors influencing the acetic acid bacteria survival rate, activity and the influence rule under liquid and solid state preservation need to be clarified fully. This topic explored the influence of liquid and solidstate preservation on the growth of ApH 1.01, indicated the effect of acidity and ethanol concentration on cell growth and physiological regulation, and compared the effects of liquid preservation and solid state preservation. Main results and conclusions are as follows:1. ApH 1.01 liquid preservation conditions: Screening incubation time, pH and ethyl alcohol are the significant factors affecting ApH 1.01 survival rate of liquid preservation by PB and BB test. The affecting order of significant factors is A(absolute alcohol) > C(pH) >B( incubation time). The appropriate liquid preservation conditions were composed of glucose1%, yeast powder 1%, acetic acid buffer(pH 5.6) 5%, calcium carbonate 0.5%, seed age18 h, inoculum quantity 10%, absolute alcohol 3.6%, pH 5.6, and 19.4h of incubation time.2. The effect of acidity and ethanol concentration on cell growth and physiological regulation: On the whole, as the extension of preservation time, the living bacteria number slowly declined at first and then decreased rapidly, acidity raised smoothly, the dehydrogenase activity appeared active and changing. With the increasing of acidity and ethanol concentration, cell morphology changed from regular oval-shape to irregular long rod-shape,capsular polysaccharide increased, ratio of unsaturated fatty acids to saturated fatty acids was increased obviously. Viability of acetic acid bacteria are greatly influenced by ethanol concentration. The interaction of ethanol and acidity appeared significant influence on the survival rate of acetic acid bacteria. Acidity 1.8 g/L and ethanol 2.8%(v/v) were suitable for acetic acid bacteria preservation.3. ApH 1.01 solid-state preservation conditions: The main influence factors are inoculation quantity, moisture content and the dosage of the bran. The affecting order of fourfactors is inoculation quantity > moisture content > dosage of the bran > inoculation time.Interaction between dosage of the bran and inoculation quantity, inoculation quantity and inoculation time are significant. The appropriate solid-state preservation conditions: bran44.9%, sterile water 51.6%, inoculum quantity 10.9%, being stored at 4℃ after 17.9 hours of incubation under 30℃.4. Liquid and solid-state preservation conditions and effect verification: Enquiring differences between the preservation effect and applicability by studying the change of viable count as time goes on under the liquid storage and solid-state storage.The results shoulded that acetic acid-ethanol liquid preservation is superior to the routine liquid preservation and solid state preservation in terms of strain viability within 45 days. When the time is more than45 days, the viable count of solid preservation is higher than acetic acid-ethanol liquid preservation and routine liquid preservation with more stable strain features. So acetic acid-ethanol liquid preservation applys to short-term preservation and solid-state preservation is suggested to long-time preservation. |
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