Acetoin (AC) is a volatile platform compound with various potential industrial applications. AC contains two stereoisomeric forms: (3)-AC and (3)-AC. Optically pure AC is an important potential intermediate and widely used as a precursor to synthesize novel optically active materials. In this study, chiral (3)-AC production from -2,3-butanediol (-2,3-BD) was obtained using recombinant cells co-expressing-2,3-butanediol dehydrogenase (-2,3-BDH), NADH oxidase (NOX), and hemoglobin protein (VHB) from sp. T241,, and , respectively. The new biocatalyst of/pET--- was developed and the bioconversion conditions were optimized. Under the optimal conditions, 86.74 g/l of (3)-AC with the productivity of 3.61 g/l/h and the stereoisomeric purity of 97.89% was achieved from 93.73 g/l -2,3-BD using the whole-cell biocatalyst. The yield and productivity were new records for (3)-AC production. The results exhibit the industrial potential for (3)-AC production via whole-cell biocatalysis.

Nonalcoholic fatty liver disease (NAFLd) is a fat metabolism disorder that occurs in liver cells. The development of NAFLd is considered to be associated with hepatic oxidative stress. The present study aimed to investigate the role of cytochrome P450 4A11 (cYP4A11) in the pathogenesis of NAFLd. The levels of plasma cYP4A11 and lipid peroxidation products levels exhibited a high correlation, and were increased significantly compared with those from normal subjects. Further in vitro studies demonstrated that the expression levels of cYP4A11 and the content of reactive oxygen species (ROS) were increased in free fatty acid (FFA)-stimulated HepG2 cells. Clofibrate, a CYP4A11 inducer, aggravated cell damage. Opposite results were observed for the cYP4A11 inhibitor HET0016, which attenuated apoptosis in FFA-treated cells. Furthermore, cYP4A11 gene overexpression and silencing were used to investigate the effects on inflammatory cytokine secretion. The data demonstrated that cYP4A11 promoted an increase in the mRNA expression of tumor necrosis factor α, interleukin (IL)-1β and IL-6 in response to FFA. In addition, western blot analysis highlighted that cYP4A11 caused an upregulation of phosphorylated p65 levels and therefore affected the NF-κB signaling pathway. The data demonstrated that cYP4A11 may metabolize fatty acids to promote the production of ROS and accelerate the progression of NAFLd.

The sonication-driven dispersion of single-walled carbon nanotubes (SWCNTs) in aqueous surfactant solution has been monitored by UV-vis-NIR spectroscopy and scanning electron microscopy. Dispersion of SWCNTs experiments reveal that the maximum concentration of dispersed SWCNTs corresponds to the maximum UV-vis-NIR absorbance of the solution. With higher surfactant concentration the dispersion rate of SWCNTs increases and low temperature sonication is required to achieve maximum dispersion. Dispersion of higher SWCNT concentrations requires longer sonication time. For effective dispersion the optimal concentration of surfactant is 1.5 wt%, the concentration of SWCNTs that can be homogeneously dispersed in aqueous solution is about 0.4 mg/ml.

Microbial contamination, especially in large-scale processes, is partly a life-or-death issue for industrial fermentation. Therefore, the aim of this research was to create an antimicrobial contamination system in Bacillus subtilis 168 (an ideal acetoin producer for its safety and acetoin synthesis potential). First, introduction of the formamidase (FmdA) from Helicobacter pylori and the phosphite dehydrogenase (PtxD) from Pseudomonas stutzeri enabled the engineered Bacillus subtilis to simultaneously assimilate formamide and phosphite as nitrogen (N) and phosphorus (P) sources. Thus, the engineered B. subtilis became the dominant population in a potentially contaminated system, while contaminated microbes were starved of key nutrients. Second, stepwise metabolic engineering via chromosome-based overexpression of the relevant glycolysis and acetoin biosynthesis genes led to a 1.12-fold increment in acetoin titer compared with the starting host. Finally, with our best acetoin producer, 25.56 g/L acetoin was synthesized in the fed-batch fermentation, with a productivity of 0.33 g/L/h and a yield of 0.37 g/g under a nonsterilized and antibiotic-free system. More importantly, our work fulfills many key criteria of sustainable chemistry since sterilization is abolished, contributing to the simplified fermentation operation with lower energy consumption and cost.

Nonalcoholic fatty liver disease (NAFLD) is a chronic hepatic disease associated with excessive accumulation of lipids in hepatocytes. As the disease progresses, oxidative stress plays a pivotal role in the development of hepatic lipid peroxidation. Cytochrome P450 1A1 (CYP1A1), a subtype of the cytochrome P450 family, has been shown to be a vital modulator in production of reactive oxygen species. However, the exact role of CYP1A1 in NAFLD is still unclear. The aim of this study was to investigate the effects of CYP1A1 on lipid peroxidation in oleic acid (OA)-treated human hepatoma cells (HepG2). We found that the expression of CYP1A1 is elevated in OA-stimulated HepG2 cells. The results of siRNA transfection analysis indicated that CYP1A1-siRNA inhibited the lipid peroxidation in OA-treated HepG2 cells. Additionally, compared with siRNA-transfected and benzo[a]pyrene (BaP)-OA-induced HepG2 cells, overexpression of CYP1A1 by BaP further accelerated the lipid peroxidation in OA-treated HepG2 cells. These observations reveal a regulatory role of CYP1A1 in liver lipid peroxidation and imply CYP1A1 as a potential therapeutic target.