野油菜黄单胞菌重组克隆pIXU9278对黄原胶生物合成的影响

Effect of Xanthomonas campestris pv. campestris recombinant clone pIXU9278 on xanthan gum biosynthesis

用ｐＩＪ３２００作为载体，构建了包含１５６２个重组克隆野生型野油菜黄单胞菌的粘粒文库，通过三亲交配法，基因文库中的重组克隆可以在ｐＲＫ２０１３的帮助下，从Ｅ．ｃｏｌｉ中转移到ＸＣＣＮＡＵ－９２中，绝大多数重组克隆对黄原胶合成无影响，但导致菌株生长缓慢。工程菌株ＸＣＣＮＡＵ－９２７８（ｐＩＸＵ９２７８）在２８℃、１２０ｒ／ｍｉｎ条件下发酵７２ｈ，产量达３７．５０ｇ／ｋｇ，发酵液粘度为１４６００ｍＰａ·ｓ，与ＸＣＣＮＡＵ－９２相比，产量增加７．１４％，发酵液粘度增加７．３５％。

The cosmid gene library including 1 562 recombinant clones of wild type Xanthomonas campestris pv. campestris was constructed, the cosmid pIJ3200 as vector. Recombinants of the cosmid gene library were transfered from E. coli into the XCCNAU 92 through the helping plasmid pRK2013 by triparent mating. Most recombinants had no effect on xanthan gum biosynthesis but lead to the lower growth. The engineering strains XCCNAU 9278 (pIXU9278) fermented at 28 ℃, 120 r/min for 72 hours, the yield reached 37.50 g/kg, the viscosity of fermented mash was 14 600 mPa·s. The yield increased by 7.14%, the viscosity by 7.35% as compared with the XCCNAU 92.