Mutation of rpoS is Beneficial for Suppressing Organic Acid Secretion During 1,3-Propandiol Biosynthesis in Klebsiella pneumoniae.

In this study, to reduce the formation of organic acid during 1,3-propanediol biosynthesis in Klebsiella pneumoniae, a method combining UV mutagenesis and high-throughput screening with pH color plates was employed to obtain K. pneumoniae mutants. When compared with the parent strain, the total organic acid formation by the mutant decreased, whereas 1,3-propanediol biosynthesis increased after 24 h anaerobic shake flask culture. Subsequently, genetic changes in the mutant were analyzed by whole-genome sequencing and verified by signal gene deletion. Mutation of the rpoS gene was confirmed to contribute to the regulation of organic acid synthesis in K. pneumoniae. Besides, rpoS deletion eliminated the formation of 2,3-butanediol, the main byproduct produced during 1,3-propanediol fermentation, indicating the role of rpoS in metabolic regulation in K. pneumoniae. Thus, a K. pneumoniae mutant was developed, which could produce lower organic acid during 1,3-propanediol fermentation due to an rpoS mutation in this study.

Regulation of Pyruvate Formate Lyase-Deficient Klebsiella pneumoniae for Efficient 1,3-Propanediol Bioproduction.

Anaerobic growth defect of pyruvate formate lyase (PFL)-deficient Klebsiella pneumoniae limits its industrial application, and the reason for this growth defect was analyzed in this study. The obtained evidences, combined with normal intracellular redox status and no further inhibition by adhE deletion, strongly suggested that growth defect in PFL-deficient K. pneumoniae was probably caused by lack of carbon flux from pyruvate to acetyl-CoA (AcCoA). Correspondingly, the anaerobic growth of PFL-deficient K. pneumoniae was promoted by deletion of pdhR, a negative transcriptional regulator gene for AcCoA generation. Through the regulation of pdhR deletion, the PFL-deficient K. pneumoniae exhibited highly efficient 1,3-propanediol production. Besides, in a 2-L fed-batch fermentation process, the cell growth of PFL-deficient K. pneumoniae strain almost recovered, when compared with that of the normal strain, and the 1,3-propanediol yield increased by 14%, while the byproducts acetate and 2,3-butanediol contents decreased by 29% and 24%, respectively.

Clinical observation on treatment with the kidney-tonifying prescription in 25 cases of postmenopausal osteoporosis.

UNLABELLED: To observe the therapeutic effects of the kidney-tonifying prescription in the treatment of postmenopausal osteoporosis (PMOP), 45 cases of PMOP were selected and randomly divided into two groups, the treatment group treated with the kidney-tonifying prescription and routine western drugs, and the control group treated with routine western drugs. After a 8-month treatment, the total effective rate of the treatment group reached 96%, obviously superior to that of the control group (50%, P < 0.05); and the level of estradiol and bone mineral density (BMD) had obviously been increased (P < 0.05). CONCLUSION: The kidney-tonifying prescription has the effects of improving the clinical symptoms, and increasing the level of estrin and BMD.