Schulte Mark J, Wiltgen Jeff, Ritter John, Mooney Charles B, Flickinger Michael C
Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, 27695.
Analytical Instrumentation Facility, North Carolina State University, Raleigh, North Carolina.
Biotechnol Bioeng. 2016 Sep;113(9):1913-23. doi: 10.1002/bit.25966. Epub 2016 Mar 28.
We propose a novel approach to continuous bioprocessing of gases. A miniaturized, coated-paper strip, high gas fraction, biocomposite absorber has been developed using slowly shaken horizontal anaerobic tubes. Concentrated Clostridium ljungdahlii OTA1 was used as a model system. These gas absorbers demonstrate elevated CO mass transfer with low power input, reduced liquid requirements, elevated substrate consumption, and increased product secretion compared to shaken suspended cells. Concentrated OTA1 cell paste was coated by extrusion onto chromatography paper. The immobilized system shows high, constant reactivity immediately upon rehydration. Cell adhesion was by adsorption to the cellulose fibers; visualized by SEM. The C. ljungdahlii OTA1 coated paper mounted above the liquid level absorbs CO and H2 from a model syngas secreting acetate with minimal ethanol. At 100 rpm shaking speed (7.7 Wm(-3) ) the optimal cell loading is 6.5 gDCW m(-2) to maintain high CO absorbing reactivity without the cells coming off of the paper into the liquid phase. Reducing the medium volume from 10 mL to 4 mL (15% of tube volume) did not decrease CO reactivity. The reduced liquid volume increased secreted product concentration by 80%. The specific CO consumption by paper biocomposites was higher at all shaking frequencies <100 rpm than suspended cells under identical incubation conditions. At 25 rpm the biocomposite outperforms suspended cells for CO absorption by 2.5-fold, with an estimated power reduction of 97% over the power input at 100 rpm. The estimated minimum kL a for miniaturized biocomposite gas-absorbers is ∼100 h(-1) , 10 to 10(4) less power input than other syngas fermentation systems reported in the literature at similar kL a. Specific consumption rates in a biocomposite were ∼14 mmol gDCW-1 h(-1) . This work intensified CO absorption and reactivity by 14-fold to 94 mmol CO m(-2) h(-1) over previous C. ljungdahlii OTA1 work by our group. Specific acetate production rates were 23 mM h(-1) or 46 mmol m(-2) h(-1) . The specific rates and apparent kL a scaled linearly with biocomposite coating area. Biotechnol. Bioeng. 2016;113: 1913-1923. © 2016 Wiley Periodicals, Inc.
我们提出了一种用于气体连续生物处理的新方法。使用缓慢振荡的水平厌氧管，开发了一种小型化的、涂有纸的、高气含率生物复合吸收器。以浓缩的Ljungdahlii梭菌OTA1作为模型系统。与振荡悬浮细胞相比，这些气体吸收器在低功率输入下表现出更高的CO传质速率、减少的液体需求、更高的底物消耗以及增加的产物分泌。通过挤压将浓缩的OTA1细胞糊剂涂覆在层析纸上。固定化系统在再水化后立即显示出高且恒定的反应性。细胞通过吸附到纤维素纤维上实现黏附；通过扫描电子显微镜观察可见。置于液面上方的Ljungdahlii梭菌OTA1涂覆纸从分泌乙酸且乙醇含量极低的合成气模型中吸收CO和H2。在100 rpm的振荡速度（7.7 Wm(-3)）下，最佳细胞负载量为6.5 gDCW m(-2)，以维持高CO吸收反应性，同时细胞不会从纸上脱落进入液相。将培养基体积从10 mL减少到4 mL（管体积的15%）不会降低CO反应性。液体体积的减少使分泌产物浓度提高了80%。在所有低于100 rpm的振荡频率下，纸基生物复合材料的比CO消耗率均高于相同培养条件下的悬浮细胞。在25 rpm时，生物复合材料在CO吸收方面比悬浮细胞性能优2.5倍，估计功率比100 rpm时的功率输入降低了97%。小型化生物复合气体吸收器的估计最小kL a约为100 h(-1)，与文献中报道的其他类似kL a的合成气发酵系统相比，功率输入降低了10至10(4)倍。生物复合材料中的比消耗率约为14 mmol gDCW-1 h(-1)。与我们团队之前关于Ljungdahlii梭菌OTA1的工作相比，这项工作将CO吸收和反应性提高了14倍，达到94 mmol CO m(-2) h(-1)。乙酸的比生产率为23 mM h(-1)或46 mmol m(-2) h(-1)。比速率和表观kL a与生物复合涂层面积呈线性比例关系。《生物技术与生物工程》2016年；113：1913 - 1923。© 2016威利期刊公司
