Abstract:
A reactor with silicone tubes as support medium was used for glycerol fermentation. The experimental set-up consisted of three phases. In P1, the applied glycerol loading rate (gly-LR) was in the range of 6-10 g.L-1.d-1 at an influent pH of 7.9 ± 0.4. In P2, gly-LR was kept constant (18.0 ± 1.8 g.L-1.d-1) with different doses of NaHCO3. Finally in P3, two different gly-LR (9 and 18 g.L-1.d-1) were evaluated, dosing 1 g-NaHCO3 per g-COD of glycerol. Glycerol consumption was close 90%. The main end-product was 1,3-propanediol (1,3-PDO) (0.40 mol.mol-gly-1), but ethanol was also generated, particularly at pH above 8 and low gly-LR (0.20 mol.mol-gly-1). After 1-year operation with glycerol as the only carbon source, a drastic shift in the bacterial community was observed. The 1,3-PDO producers Lacrimispora and Clostridium became dominant, although non-glycerol-degrading fermentative genera, e.g., Actinomyces and Eubacterium, thrived at the expense of cellular breakdown products.
摘要:
用硅胶管作为支持培养基的反应器用于甘油发酵。实验设置由三个阶段组成。在P1中,所施加的甘油负载率(gly-LR)在6-10g的范围内。L-1.d-1,进水pH为7.9±0.4。在P2中,gly-LR保持恒定(18.0±1.8g。L-1.d-1)用不同剂量的NaHCO3。最后在P3中,两种不同的gly-LR(9和18g。L-1.D-1)进行了评估,每g-COD甘油加入1g-NaHCO3。甘油消耗接近90%。主要的最终产物是1,3-丙二醇(1,3-PDO)(0.40mol。mol-gly-1),但是乙醇也产生了,特别是在pH高于8和低gly-LR(0.20mol。mol-gly-1)。以甘油为唯一碳源运行1年后,观察到细菌群落的急剧变化。1,3-PDO生产者Lacrimispora和Clostridium成为主导,虽然非甘油降解发酵属,例如,放线菌和真细菌,以细胞分解产物为代价的繁荣。