Reconfiguration of the reductive TCA cycle enables high-level succinic acid production by Yarrowia lipolytica.

Succinic acid (SA) is an important C4-dicarboxylic acid. Microbial production of SA at low pH results in low purification costs and hence good overall process economics. However, redox imbalances limited SA biosynthesis from glucose via the reductive tricarboxylic acid (TCA) cycle in yeast. Here, we engineer the strictly aerobic yeast Yarrowia lipolytica for efficient SA production without pH control. Introduction of the reductive TCA cycle into the cytosol of a succinate dehydrogenase-disrupted yeast strain causes arrested cell growth. Although adaptive laboratory evolution restores cell growth, limited NADH supply restricts SA production. Reconfiguration of the reductive SA biosynthesis pathway in the mitochondria through coupling the oxidative and reductive TCA cycle for NADH regeneration results in improved SA production. In pilot-scale fermentation, the engineered strain produces 111.9 g/L SA with a yield of 0.79 g/g glucose within 62 h. This study paves the way for industrial production of biobased SA.

Analysis of the effect of anti-tuberculosis therapy combined with all-in-one nursing care on the alleviation of inflammation in patients with pulmonary tuberculosis.

To analyze the application effect of anti-tuberculosis therapy (ATT) combined with all-in-one nursing care on pulmonary tuberculosis (PT). Seventy-four PT patients who received ATT in our hospital between December 2015 and June 2016 were selected as the research participants and randomized into a research group (RG; n=37) and a control group (CG; n=37) that were given all-in-one nursing care and routine care, respectively. The cure rate and treatment compliance were compared between groups, and the awareness of disease prevention and treatment was investigated. Patients' psychological status and quality of life were evaluated using the Self-Rating Depression/Anxiety Scale (SAS/SDS) and the Quality of Life Questionnaire Core 30 (QLQ-C30), respectively. RG and CG were not statistically different in the clinical cure rate (P>0.05), but the X-ray cure rate was higher and the recurrence rate was lower in RG (P<0.05). In addition, RG showed higher medication compliance rate, regular reexamination rate and awareness of disease prevention and treatment than CG (P<0.05). Reductions in SAS/SDS scores were observed in both groups after care, with even lower levels in RG, while the QLQ-C30 score increased and was higher in RG as compared to CG (P<0.05). Therefore, All-in-one nursing care can effectively enhance the level of treatment compliance and awareness of disease prevention and treatment of PT patients. In the future, when treating PT patients in the clinic, the effectiveness of ATT can be improved by implementing all-in-one nursing care to provide more reliable prognosis for patients.

Biosynthesis of α-Pinene by Genetically Engineered Yarrowia lipolytica from Low-Cost Renewable Feedstocks.

α-Pinene, an important biologically active natural monoterpene, has been widely used in fragrances, medicines, and fine chemicals, especially, in high-density renewable fuels such as jet fuel. The development of an α-pinene production platform in a highly modifiable microbe from renewable substitute feedstocks could lead to a green, economical avenue, and sustainable biotechnological process for the biosynthesis of α-pinene. Here, we report engineering of an orthogonal biosynthetic pathway for efficient production of α-pinene in oleaginous yeast Yarrowia lipolytica that resulted in an α-pinene titer of 19.6 mg/L when using glucose as the sole carbon source, a significant 218-fold improvement than the initial titer. In addition, the potential of using waste cooking oil and lignocellulosic hydrolysate as carbon sources for α-pinene production from the engineered Y. lipolytica strains was analyzed. The results indicated that α-pinene titers of 33.8 and 36.1 mg/L were successfully obtained in waste cooking oil and lignocellulosic hydrolysate medium, thereby representing the highest titer reported to date in yeast. To our knowledge, this is also the first report related to microbial production of α-pinene from waste cooking oil and lignocellulosic hydrolysate.