Lignocellulose-derived inhibitory compounds formed during the harsh pretreatment of biomass often inhibits or delays microbial growth, necessitating detoxification of hydrolysates before microbial fermentation. In this study the Corn Stover (CS) hydrolysate, derived from 15 % solid loading of CS-biomass, contained sugars (37 g/L glucose, 75 g/L total reducing sugars), but also contains inhibitors that inhibited the growth of oleaginous yeast. This study identified CaCO3 treatment at a concentration 0.4 % as the most efficient strategy to detoxify 15 % CS-hydrolysate, ensuring optimal growth of Rhodosporidium toruloides. In the CaCO3-treated CS-hydrolysate, maximum growth was achieved on day 5 (17 g/L dry cell biomass, 8 g/L lipid) while as in untreated hydrolysate no growth was observed. The CS-hydrolysate derived from a high-solid loading of CS-biomass that supported the growth of R. toruloides after CaCO3 treatment reached 21 % (solid loading), as compared to only 10 % observed for the untreated hydrolysate. Experiments with different calcium salts at low concentration (0.05 %) were ineffective in detoxifying the CS-hydrolysate, ruling out calcium deficiency as the cause of toxicity. Additionally, gas chromatography (GC) analysis of the recovered CaCO3 indicated that it did not bind to the inhibitors present in the hydrolysate. Lipid production and growth of R. toruloides were compared in CaCO3-treated and untreated CS-hydrolysates. Both supported growth at 10 % solid loading, with treated hydrolysate yielding 15 g/L biomass (39 % lipids) and untreated yielding 11 g/L biomass (34 % lipids). This study emphasizes the importance of CaCO3-mediated detoxification in facilitating the bioconversion of lignocellulosic biomass for biofuel production.

中文翻译：

---

碳酸钙介导的玉米秸秆水解物解毒促进圆孢子虫发酵

在对生物质进行苛刻的预处理过程中形成的木质纤维素衍生的抑制化合物通常会抑制或延缓微生物生长，因此需要在微生物发酵之前对水解产物进行解毒。在这项研究中，玉米秸秆 （CS） 水解物来源于 CS 生物质的 15% 固体负载，含有糖（37 g/L 葡萄糖，75 g/L 总还原糖），但也含有抑制油性酵母生长的抑制剂。本研究确定浓度为 0.4 % 的 CaCO3 处理是解毒 15 % CS 水解物的最有效策略，确保圆盘红孢子虫的最佳生长。在 CaCO 3 处理的 CS 水解物中，第 5 天达到最大生长（17 g/L 干细胞生物量，8 g/L 脂质），而与未处理的水解物一样，未观察到生长。在 CaCO3 处理后，支持 R. toruloides 生长的 CS 水解物来自高固体含量的 CS 生物质，达到 21%（固体含量），而未处理的水解物仅观察到 10%。使用低浓度 （0.05%） 的不同钙盐的实验对 CS 水解物的解毒无效，排除了钙缺乏是毒性的原因。此外，回收的 CaCO3 的气相色谱 （GC） 分析表明，它不与水解产物中存在的抑制剂结合。比较了 CaCO3 处理和未处理的 CS 水解物中 R. toruloides 的脂质产生和生长。两者都支持在 10% 固体负载下生长，处理后的水解物产生 15 g/L 生物质（39% 脂质），未处理产生 11 g/L 生物质（34% 脂质）。本研究强调了 CaCO3 介导的解毒在促进木质纤维素生物质用于生物燃料生产的生物转化中的重要性。