Succinic acid is one of the most useful intermediate chemicals that can be produced in a biorefinery approach.In this study,Actinobacillus succinogenes was immobilized to produce succinic acid using non-detoxified cor...Succinic acid is one of the most useful intermediate chemicals that can be produced in a biorefinery approach.In this study,Actinobacillus succinogenes was immobilized to produce succinic acid using non-detoxified corn fiber hydrolysate(CFH)and a control mimicking the sugars in CFH.Tests were carried out in a hollow fiber membrane packed-bed biofilm reactor(HFM–PBR)operated in a continuous mode.Under steady-state conditions,the bioconversion process was characterized in terms of sugar consumption,succinic acid and other organic acid production.Steady states were obtained at dilution rates of 0.025,0.05,0.075,0.1,0.2,and 0.3 h^(-1).The optimal results were achieved at the dilution rate of 0.05 h^(-1)and recirculation rate of 50 ml/min with a maximum succinic acid concentration,yield and productivity of 31.1 g/L,0.61 g/g and 1.56 g/L h,respectively,when control was used.Succinic acid concentration,yield and productivity of 23.4 g/L,0.51 g/g and 1.17 g/L h,respectively,were obtained when CFH was used.Productivity in the HFM–PBR was between 1.3 and 1.9 times higher than productivities for succinic acid production from CFH stated in the literature.The results demonstrated that immobilized A.succinogenes has the potential for effective conversion of an inexpensive biomass feedstock to succinic acid.Furthermore,the process has the potential to serve as a means for value-added chemical biomanufacturing in an integrated corn biorefinery.展开更多
基金The authors wish to acknowledge the Nebraska Corn Board for funding this work under award number 88-R-1718-01the financial support of the University of Nebraska-Lincoln Agricultural Research Division.
文摘Succinic acid is one of the most useful intermediate chemicals that can be produced in a biorefinery approach.In this study,Actinobacillus succinogenes was immobilized to produce succinic acid using non-detoxified corn fiber hydrolysate(CFH)and a control mimicking the sugars in CFH.Tests were carried out in a hollow fiber membrane packed-bed biofilm reactor(HFM–PBR)operated in a continuous mode.Under steady-state conditions,the bioconversion process was characterized in terms of sugar consumption,succinic acid and other organic acid production.Steady states were obtained at dilution rates of 0.025,0.05,0.075,0.1,0.2,and 0.3 h^(-1).The optimal results were achieved at the dilution rate of 0.05 h^(-1)and recirculation rate of 50 ml/min with a maximum succinic acid concentration,yield and productivity of 31.1 g/L,0.61 g/g and 1.56 g/L h,respectively,when control was used.Succinic acid concentration,yield and productivity of 23.4 g/L,0.51 g/g and 1.17 g/L h,respectively,were obtained when CFH was used.Productivity in the HFM–PBR was between 1.3 and 1.9 times higher than productivities for succinic acid production from CFH stated in the literature.The results demonstrated that immobilized A.succinogenes has the potential for effective conversion of an inexpensive biomass feedstock to succinic acid.Furthermore,the process has the potential to serve as a means for value-added chemical biomanufacturing in an integrated corn biorefinery.
文摘针对膜生物膜反应器(MBf R)研究中疏水性微孔膜供氧能力不足、耐污染性较差等问题,采用自聚合法对自制疏水性聚偏氟乙烯(PVDF)中空纤维膜进行表面改性,研究制备适用于MBf R技术的PVDF/p DOPA中空纤维复合膜。选取典型有机污染物牛血清白蛋白(BSA),考察原膜及表面改性膜的抗污染性能,并采用XDLVO理论定量解析BSA对PVDF原膜及PVDF/p DOPA改性膜的污染行为。研究结果表明,改性膜对BSA的吸附速率低于原膜,最终BSA吸附量为原膜的62.1%,进一步的氧传质实验表明BSA污染后,改性膜的氧总转移系数衰减率(14.0%)低于原膜(21.9%),显示出优于原膜的抗污染性能。XDLVO理论所涉及到的三种界面自由能中,粘附阶段和粘聚阶段的极性力界面自由能均起主导作用,决定总界面自由能的性质,范德华力界面自由能和静电力界面自由能绝对值相对较小,对膜污染影响较为微弱;PVDF/p DOPA改性膜与BSA之间的总表面自由能(10.53 m J/m2)远大于PVDF原膜(-12.52 m J/m2),较好的解释了原膜与改性膜耐污染性能的差异。
