Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA.
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA; Joint BioEnergy Institute (JBEI), Emeryville, CA 94608, USA.
Bioresour Technol. 2024 Jan;391(Pt A):129854. doi: 10.1016/j.biortech.2023.129854. Epub 2023 Oct 18.
Anaerobic gut fungi (AGF) have potential to valorize lignocellulosic biomass owing to their diverse repertoire of carbohydrate-active enzymes (CAZymes). However, AGF metabolism is poorly understood, and no stable genetic tools are available to manipulate growth and metabolic flux to enhance production of specific targets, e.g., cells, CAZymes, or metabolites. Herein, a cost-effective, Arduino-based, continuous-flow anaerobic bioreactor with online optical density control is presented to probe metabolism and predictably tune fluxes in Caecomyces churrovis. Varying the C. churrovis turbidostat setpoint titer reliably controlled growth rate (from 0.04 to 0.20 h), metabolic flux, and production rates of acetate, formate, lactate, and ethanol. Bioreactor setpoints to maximize production of each product were identified, and all continuous production rates significantly exceed batch rates. Formate spike-ins increased lactate flux and decreased acetate, ethanol, and formate fluxes. The bioreactor and turbidostat culture schemes demonstrated here offer tools to tailor AGF fermentations to application-specific hydrolysate product profiles.
厌氧肠道真菌（AGF）由于其多样化的碳水化合物活性酶（CAZymes） repertoire，具有木质纤维素生物质增值的潜力。然而，AGF 的代谢过程还不太清楚，也没有稳定的遗传工具可用于操纵生长和代谢通量，以增强特定目标的生产，例如细胞、CAZymes 或代谢物。本文提出了一种基于 Arduino 的经济型连续流厌氧生物反应器，具有在线光密度控制功能，可用于研究 Caecomyces churrovis 的代谢，并可预测性地调节其通量。通过改变 C. churrovis 恒浊培养物设定点滴度，可可靠地控制生长速率（从 0.04 到 0.20 h）、代谢通量和乙酸盐、甲酸盐、乳酸盐和乙醇的生产速率。确定了使每种产物产量最大化的生物反应器设定点，所有连续生产速率均显著超过分批生产速率。甲酸盐的添加增加了乳酸盐的通量，降低了乙酸盐、乙醇和甲酸盐的通量。本文展示的生物反应器和恒浊培养物方案为定制 AGF 发酵以适应特定水解产物图谱提供了工具。
