ABSTRACT
BACKGROUND: Fed-batch fermentation has been conventionally implemented for the production of lactic acid with a high titer and high productivity. However, its operation needs a complicated control which increases the production cost. RESULTS: This issue was addressed by simplifying the production scheme. Escherichia coli was manipulated for its glycerol dissimilation and d-lactate synthesis pathways and then subjected to adaptive evolution under high crude glycerol. Batch fermentation in the two-stage mode was performed by controlling the dissolved oxygen (DO), and the evolved strain deprived of poxB enabled production of 100 g/L d-lactate with productivity of 1.85 g/L/h. To increase productivity, the producer strain was further evolved to improve its growth rate on crude glycerol. The fermentation was performed to undergo the aerobic growth with low substrate, followed by the anaerobic production with high substrate. Moreover, the intracellular redox of the strain was balanced by fulfillment of the anaerobic respiratory chain with nitrate reduction. Without controlling the DO, the microbial fermentation resulted in the homofermentative production of d-lactate (ca. 0.97 g/g) with a titer of 115 g/L and productivity of 3.29 g/L/h. CONCLUSIONS: The proposed fermentation strategy achieves the highest yield based on crude glycerol and a comparable titer and productivity as compared to the approach by fed-batch fermentation. It holds a promise to sustain the continued development of the crude glycerol-based biorefinery.
ABSTRACT
OBJECTIVE: To assess the clinical significance of low compliance bladder (LCB) in women with lower urinary tract symptoms. MATERIALS AND METHODS: Medical records of 1490 women undergoing videourodynamic studies (VUSs) were reviewed. Comprehensive medical histories, physical examinations, bladder diaries, and results of multichannel VUS were analyzed. This study adopted an end filling detrusor pressure (EFP) greater than 20 cmH2O to define LCB. RESULTS: Among the study patients (n = 1490), 9.1% were diagnosed with LCB using a cutoff value of 17.5 cmH2O, which had a sensitivity and specificity of 89% and 92.7%, respectively. Results of multivariate analysis indicated that age (p = 0.005), maximum cystometric capacity (MCC; p = 0.002), detrusor overactivity (DO; p = 0.001), pelvic organ prolapse (POP; p = 0.018), recurrent urinary tract infection (p = 0.001), and radical abdominal hysterectomy (RAH; p < 0.001) as independent prognostic factors. Furthermore, our study results indicate that the MCC, urinary tract infection, and a history of RAH have a positive correlation with LCB, whereas, age, POP, and DO have a negative correlation with LCB. CONCLUSION: Our idea using EFP (≥17.5 cmH2O) for screening women with LCB is feasible for clinical use.
