The Study Of Synergistic Effects And Regulation Of Cell Population For Sugarcane Molasses Wastewater To Produce Phenylethanol

Resource utilization of wastewater has attracted intensive attentions due to therequirements of environmental protection and sustainable development. Herein，2-phenylethanol (2-PE) production using cane molasses wastewater (CMW) wasstudied. Firstly, the microbial mixed culture (MMC) endured6g/L2-PE wasscreened and adapted by repeated batch cultivations. Secondly, process parametersfor2-PE production were optimized and the highest2-PE production of988mg/Lwas obtained at temperature35°C, pH7.0and airflow rate0.8vvm in batch culture.Subsequently, continuous2-PE production was carried out in an internal airlift loopreactor (IALR). A highest838mg/L2-PE production with a yield of8.4mg/g-COD was achieved at hydraulic retention time of4days. Finally, thestructural evolution and the function characteristics of the MMC were analyzedusing denaturing gradient gel electrophoresis.To elucidate the cooperation mechanisms of the MMC overcomingenvironment stress to enhance2-PE production,102intracellular metabolites wereidentified using GC-MS and LC-MS/MS. By multivariate statistical analysis ofPCA and PLS,11metabolites including Phe, USFA18, PYR, Tyr, Trp, Glu, Pro,ACE, LAC, Thr and Leu were seemed as the potential target regulatory factor toenhance2-PE production according to the VIP score. Furthermore, rational feedingstrategy of the key factors were conducted. The results of batch combinationfeeding showed that2-PE production increased64.7%from988mg/L to1627mg/L. After a continuous regular interval combination feeding, the2-PEproduction was up to1437mg/L with an average field of13.3mg/g-COD at thestable operation stage of the reactor. Additionally, the average COD removalincreased9.3%to83.7%. From the feeding results it can be seen that a higher2-PEproduction and a higher organic load removal were obtained.By the resource utilization, the COD of CMW decreased to21g/L from theoriginal130g/L. However, a high COD concentration and color still existed in thefermentation wastewater and need to be treated furthermore. After the firstanaerobic treatment by UASB, a83.8%COD removal rate and a367mL/g-CODmethane yield were achieved. After the secondary anaerobic treatment by AF, the COD removal rate was94.3%with a197mg/L of effluent COD and have met thenational secondary emission standards. After a deep aeration treatment by BAF,COD, BOD, SS and pH of the effluent except NH3-N have met the national firstemission standards (GB8978-1996). Finally, the combination of UASB, AF andBAF were used to continuously treat the fermentation wastewater. Thecombination of the reactors showed a better performance than the independentreactor during a continuous operation of40d. All the parameters of the effluentincluding NH3-N meet the national first emission standards (GB8978-1996).