Two Transformation Bacteria Nutrition Physiological Studies In 2-Step-Fermentation

Vitamin C, as known L-ascorbic acid, is one of the most important water-soluble vitamins. It has been widely used due to its important physiological functions. At present, the huge production of the vitamin C in China has taken up more than 90 % of the global yield and more than 80 % output is exported.“Two-step fermentation method”is the unique method producing the vitamin C in China: in the first-step fermentation process, D-sorbitol is converted into L-sorbose by the oxidation of Acetobacter melanogenuim; in the second-step mix fermentation process, L-sorbose is transformed into 2-keto-L-gulonic acid (2-KGA). At the last step, the 2-KGA is changed into vitamin C through chemical method. In the second step, the mix fermentation is realized by the cooperation of the two different strains: Bacillus megaterium and Ketogulinigenium vulgare which are commonly called as mega- and micro-bacteria respectively. Now, more than 90% sorbose can be converted into KGA through mix fermentation, but the basic physiological relationship between the two strains is still unclear. In this paper, the intrinsic relationship between the mixed bacterium is studied.The main results are shown as follows:(1) created can fast and accurate screening of substrate screening model transformation, the results showed that the acetic acid bacteria AS1.114 and raw ketone cologne acid bacteria can be quickly transformed mannitol, glycerin, glucose, fructose, xylose, ethanol, and sorbitol generating the corresponding aldehyde or acid, acetic acid bacteria AS1.114 sorbic sugar, born into kd03 although ketone cologne acid bacteria could transmute the sorbic sugar generation 2 - ketone-gologne acid, but slower than other substrates, so not the best nutrients growth.(2) proved AS1.114 acetic acid bacteria can transformation from sorbose into sorbitol effectively, transformation glucose into glucose sour, xylose into xylose acid, acetic acid, different substrate concentration, transformative speed, nutritional requirements, especially the pure cellular can transformation for three generations;①the highest transformation sorbitol reached to 24 % in 90 h;②the highest transformation of glucose reached to 20 % in 118 h;③transformation xylose reached to 10 % in 140 h;④the highest transformation concentration of ethanol reached to 7 % in 120 h;⑤can’t transformation sorbose;(3) in the study of the relationship between the size of bacteria in the process, first discovered a factor of mixed bacteria FA of big bacteria can promote spores of large bacteria growth alone without promoting phenomenon, this also is a further indication the complexity of bacteria associated relationship between the size of small bacteria: big bacteria produce acids promote not only provides nutrition, is an interactive process two kinds of bacteria.①Creening promote factor can make the K. vulgare grow alone, the colony grew well, passage stability;②Promote factor FA can promote the Bacillus sp. spores ahead in mixed bacteria fermenting;③Promote factor AS can make K. vulgare alone ferment produce acid rate as much as the mixed bacteria,④Promote factor DA can make the mixed bacteria ferment produce acid ahead;⑤Promote factor AS and FD can make substrate concentration reached 10 % in the mixed fermentationIn this paper the innovation points has the following four:⑴established the screening system of substrate is very simplely, rapidly, its can also be used to other oxidation substrate screening during our work;⑵For the relationship between the mixed bacteria further research have been made, especially in the nutrition physiological ,have made a prominent found , screen some promote factors,which can make K. vulgare grown alonely, Genetic stability and produce acid rate reached the mixed bacteria ferment, the discover pointed out the new research direction for the mixed fermentation of bacteria, In the production practice, also have significance value guidance;⑶First found promote factor FA can promote the Bacillus sp. spores aheadly in mixed bacteria fermenting;⑷the several promoting factors can make the substrate concentration reached to 10 % during mixed fermentation , its production acid rate higher 11.8 % more than the matched group, Has a great guidance for industrial production.