Liu Guang-Lei, Bu Xian-Ying, Chen Chaoyang, Fu Chunxiang, Chi Zhe, Kosugi Akihiko, Cui Qiu, Chi Zhen-Ming, Liu Ya-Jun
College of Marine Life Sciences, Ocean University of China, Qingdao, 266101, People's Republic of China.
Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266101, China.
Biotechnol Biofuels Bioprod. 2023 Jan 17;16(1):9. doi: 10.1186/s13068-023-02260-z.
Lignocellulose is a valuable carbon source for the production of biofuels and biochemicals, thus having the potential to substitute fossil resources. Consolidated bio-saccharification (CBS) is a whole-cell-based catalytic technology previously developed to produce fermentable sugars from lignocellulosic agricultural wastes. The deep-sea yeast strain Rhodotorula paludigena P4R5 can produce extracellular polyol esters of fatty acids (PEFA) and intracellular single-cell oils (SCO) simultaneously. Therefore, the integration of CBS and P4R5 fermentation processes would achieve high-value-added conversion of lignocellulosic biomass.
The strain P4R5 could co-utilize glucose and xylose, the main monosaccharides from lignocellulose, and also use fructose and arabinose for PEFA and SCO production at high levels. By regulating the sugar metabolism pathways for different monosaccharides, the strain could produce PEFA with a single type of polyol head. The potential use of PEFA as functional micelles was also determined. Most importantly, when sugar-rich CBS hydrolysates derived from corn stover or corncob residues were used to replace grain-derived pure sugars for P4R5 fermentation, similar PEFA and SCO productions were obtained, indicating the robust conversion of non-food corn plant wastes to high-value-added glycolipids and lipids. Since the produced PEFA could be easily collected from the culture via short-time standing, we further developed a semi-continuous process for PEFA production from corncob residue-derived CBS hydrolysate, and the PEFA titer and productivity were enhanced up to 41.1 g/L and 8.22 g/L/day, respectively.
Here, we integrated the CBS process and the P4R5 fermentation for the robust production of high-value-added PEFA and SCO from non-food corn plant wastes. Therefore, this study suggests a feasible way for lignocellulosic agro-waste utilization and the potential application of P4R5 in industrial PEFA production.
木质纤维素是生产生物燃料和生物化学品的宝贵碳源，因此有潜力替代化石资源。联合生物糖化（CBS）是一种基于全细胞的催化技术，此前已被开发用于从木质纤维素农业废弃物中生产可发酵糖。深海酵母菌株沼泽红酵母P4R5能够同时产生细胞外脂肪酸多元醇酯（PEFA）和细胞内单细胞油（SCO）。因此，CBS和P4R5发酵过程的整合将实现木质纤维素生物质的高附加值转化。
菌株P4R5能够共同利用葡萄糖和木糖（木质纤维素的主要单糖），还能高水平利用果糖和阿拉伯糖来生产PEFA和SCO。通过调节不同单糖的糖代谢途径，该菌株能够生产具有单一类型多元醇头部的PEFA。还确定了PEFA作为功能性微胶粒的潜在用途。最重要的是，当使用源自玉米秸秆或玉米芯残渣的富含糖的CBS水解产物替代谷物来源的纯糖用于P4R5发酵时，获得了相似的PEFA和SCO产量，这表明非粮玉米植物废弃物能够强劲地转化为高附加值的糖脂和脂质。由于所产生的PEFA可通过短时间静置从培养物中轻松收集，我们进一步开发了一种从玉米芯残渣衍生的CBS水解产物中生产PEFA的半连续工艺，PEFA滴度和生产率分别提高到了41.1 g/L和8.22 g/L/天。
在此，我们整合了CBS工艺和P4R5发酵，以从非粮玉米植物废弃物中强劲地生产高附加值的PEFA和SCO。因此，本研究为木质纤维素农业废弃物的利用以及P4R5在工业PEFA生产中的潜在应用提出了一种可行的方法。
