A novel method based on pH value was proposed to simplify the substrate feeding method for glutamic acid fermentation. The linear relationship between the consumption amounts of ammonia (x) and that of glucose (y) was established (y = 7.4744x, R2 = 0.9989) which could be used as the ratio of the amount of ammonia and that of glucose in the feeding broth. Thus the concentration of glucose could be controlled through the adjustment of pH automatically. In the glutamic acid fermentation using the pH feedback-controlled glucose feeding method, the glucose concentration in fermentation broth was maintained between 12 and 21 g/L. Compare with the constant glucose concentration feeding method, the glucose conversion rate and glutamic acid productivity increased by 9.06% and 17.5% respectively, when the pH feedback-controlled glucose feeding method was employed, and fermentation period was shorten above 2 h.
Bioreactors ; microbiology ; Corynebacterium glutamicum ; growth & development ; metabolism ; Culture Techniques ; Feedback ; Fermentation ; Glucose ; metabolism ; Glutamic Acid ; biosynthesis ; metabolism ; Hydrogen-Ion Concentration ; Quaternary Ammonium Compounds ; metabolism

Objective:To propose a monosegment thoracic and lumbar fracture dislocation (mTLFD) classification, and to evaluate its reliability and clinical application.Methods:All of 298 cases of thoracic and lumbar fracture dislocation who received surgical management in our hospital from January 2014 to December 2019 were retrospectively analyzed. 123 cases were included in the study according to inclusion and exclusion criteria. mTLFD classification was proposed based on the imaging characteristics: type I (intervertebral disc injury mainly) and type II (vertebral burst fracture mainly). The type II was classified based on distribution of injury segment: type IIa (T 11 and above) and Ttype IIb (below T 11). Six spinal surgeons (3 residents, 3 associate chief physicians) were selected to classify the 123 cases according to preoperative imaging data, and to perform reliability test of each type. The repeatability and reliability of the classification were evaluated by ICC index. Different management strategies were performedf or each type: type I was managed with posterior decompression interbody fusion and internal fixation; type IIa underwent posterior decompression and fixation, subtotal vertebral resection and fusion was performed if bony compromise was still present through intra-operative exploration. Type IIb underwent posterior decompression, posterolateral fusion and internal fixation on the first stage, while anterior subtotal vertebral resection and reconstruction was performed on the second stage if the bony compromise was still present based on post-operative CT examination. The American Spinal Injury Association (ASIA) grading of all patients was recorded, and the visual analogue scale (VAS), Oswetry disability Iindex (ODI) and local Cobb angle of each type was compared between pre-operation and final follow-up. Results:The average follow-up time of all patients was 10.4±1.8 months. The average repeatability and reliability ICC index of mTLFD of 3 residents and 3 deputy chief physicians were 0.926 and 0.964, respectively, and 0.746 and 0.907, respectively. The reliability ICC index of type I, type IIa and type IIb was 0.918, 0.947 and 0.962, respectively, and the repeatability ICC index was 0.930, 0.940 and 0.966, respectively. The neurological function recovery was obtained in 56 patients. The preoperative VAS of type I, type IIa and type IIb were 8.5±1.0, 8.4±1.0 and 8.3±0.9, and 2.0±1.1, 1.8±1.0 and 1.8±0.9 at the final follow-up (all P<0.001). The ODI of type I, type IIa and type IIb were 97.0%±2.1%, 97.1%±1.9% and 97.3%±2.1% before surgery, and 29.5%±6.8%, 27.0%±6.0% and 29.0%±6.7% at the final follow-up (all P<0.001). The local Cobb angles of type I, type IIa and type IIb were 20.9°±7.1°, 29.0°±9.1° and 26.4°±6.9° before surgery, and 12.5°±5.4°, 18.0°±9.1° and 13.1°±5.1° at the final follow-up (all P<0.001). Conclusion:The mTLFD classification proposed in this study has strong repeatability and reliability, and management strategy of each type have achieved satisfactory clinical efficacy, indicating that the classification has certain significance for management of thoracic and lumbar spine fracture dislocation.