Enhanced production of succinic acid from methanol-organosolv pretreated Strophanthus preussii by recombinant Escherichia coli.

A biorefinery process for high yield production of succinic acid from biomass sugars was investigated using recombinant Escherichia coli. The major problem been addressed is utilization of waste biomass for the production of succinic acid using metabolic engineering strategy. Here, methanol extract of Strophanthus preussii was used for fermentation. The process parameters were optimized. Glucose (9 g/L), galactose (4 g/L), xylose (6 g/L) and arabinose (0.5 g/L) were the major sugars present in the methanol extract of S. preussii. E. coli K3OS with overexpression of soluble nucleotide pyridine transhydrogenase sthA and mutation of lactate dehydrogenase A (ldhA), phosphotransacetylase acetate kinase A (pta-ackA), pyruvate formate lyase B (pflB), pyruvate oxidase B (poxB), produced a final succinic acid concentration of 14.40 g/L and yield of 1.10 mol/mol total sugars after 72 h dual-phase fermentation in M9 medium. Here, we show that the maximum theoretical yield using methanol extracts of S. preussii was 64%. Hence, methanol extract of S. preussii could be used for the production of biochemicals such as succinate, malate and pyruvate.

Effect of tenofovir, an antiretroviral drug, on hepatic and renal functional indices of Wistar rats: protective role of vitamin E.

BACKGROUND: Tenofovir (TFR) is a nucleotide reverse transcriptase inhibitor with activity against human immunodeficiency virus. We studied the effect of TFR administered to Wistar rats on hepatic and renal function markers and the possible modulatory role of vitamin E (Vit E). METHODS: The study consists of four groups of six rats each. The first group served as control, the second group received TFR at 50 mg/kg/day for 4 weeks, third group received TFR and Vit E, and the last group received Vit E alone. RESULTS: TFR administration caused a significant (p<0.05) increase in the levels of serum urea, creatinine, urinary glucose, and protein by 65%, 51%, 88%, and 79%, respectively, relative to controls. This was followed by a significant (p<0.05) reduction in creatinine clearance of TFR-treated rats. There were no significant differences (p>0.05) in the activities of serum aminotransferases, γ-glutamyltransferase, and alkaline phosphatase in TRF-treated rats relative to controls. TFR administration caused a marked elevation of malondialdehyde (MDA; index of lipid peroxidation) in the animals. Specifically, serum, hepatic, and renal MDA levels increased by 75%, 90%, and 102%, respectively. TRF-treated rats had significantly (p<0.05) reduced activities of renal catalase, glutathione-S-transferase, and superoxide dismutase. Supplementation of Vit E ameliorated TFR-induced effects by decreasing the levels of MDA and enhancing the activities of renal antioxidative enzymes. The biochemical data were supported by histopathological findings from the slides. CONCLUSIONS: TFR increased oxidative stress and altered kidney function markers in the rats, whereas supplementation of Vit E attenuated these effects.