The present application relates to an
aldehyde mutarotase
gene salA and its application in constructing a high-ADD-producing
genetically engineered mycobacterium, and a high-ADD-producing
genetically engineered mycobacterium and its construction and application in preparing 1,4-androstadiene-3,17-dione by microbial
fermentation. The high-ADD-producing
genetically engineered mycobacterium is obtained by knocking out kshA1, MnOpccR and salA genes in turn using mycobacterium as a
chassis. The genetically engineered strain provided by the present application effectively controls the generation of by-products, greatly improves the
utilization rate of steroidal substrates and the
molar conversion rate of products, simplifies the post-
processing process, and the strategy can also be applied to the synthesis of products in the common synthesis path of 1,4-androstadiene-3,17-dione and 9-OH-AD, which is
microbial transformation of
side chain degradation using
phytosterol as a substrate, completely blocks the synthesis of 4-HBC and 1,4-HBC by-products, and reduces the burden of downstream separation while improving the
utilization rate of
phytosterol substrate. The present application has certain universality, is suitable for vigorous popularization and application, and has high economic and
social benefits.