Fu Weng, Wu Shengbo, Wang Chun, Thangalazhy-Gopakumar Suchithra, Kothari Urvi, Shi Suan, Han Lujia
Engineering Laboratory for Agro Biomass Recycling & Valorizing, College of Engineering, China Agricultural University, Beijing 100083, China.
Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, Semenyih 43500, Selanggor, Malaysia.
Bioengineering (Basel). 2023 Oct 14;10(10):1197. doi: 10.3390/bioengineering10101197.
The prehydrolysate from dilute acid pretreatment of lignocellulosic feedstocks often contains inhibitory compounds that can seriously inhibit the subsequent enzymatic and fermentation processes. Acetic acid is one of the most representative toxic compounds. In this research, alkaline deacetylation of corn stover was carried out using sodium carbonate under mild conditions to selectively remove the acetyl groups of the biomass and reduce the toxicity of the prehydrolysate. The deacetylation process was optimized by adjusting factors such as temperature, treatment time, and sodium carbonate concentration. Sodium carbonate solutions (26 wt%) at 3050 °C were used for the deacetylation step, followed by dilute acid pretreatment with 1.5% HSO at 121 °C. Results showed that the acetyl content of the treated corn stover could be reduced up to 87%, while the hemicellulose loss remained low. The optimal deacetylation condition was found to be 40 °C, 6 h, and 4 wt% NaCO, resulting in a removal of 80.55% of the acetyl group in corn stover and a hemicellulose loss of 4.09%. The acetic acid concentration in the acid prehydrolysate decreased from 1.38 to 0.34 g/L. The enzymatic hydrolysis of solid corn stover and the whole slurry after pretreatment increased by 17% and 16%, respectively.
木质纤维素原料经稀酸预处理后的预水解产物通常含有抑制性化合物，这些化合物会严重抑制后续的酶解和发酵过程。乙酸是最具代表性的有毒化合物之一。在本研究中，在温和条件下使用碳酸钠对玉米秸秆进行碱性脱乙酰化，以选择性地去除生物质中的乙酰基并降低预水解产物的毒性。通过调节温度、处理时间和碳酸钠浓度等因素对脱乙酰化过程进行了优化。在3050°C下使用26 wt%的碳酸钠溶液进行脱乙酰化步骤，然后在121°C下用1.5%的硫酸进行稀酸预处理。结果表明，处理后的玉米秸秆的乙酰含量可降低高达87%，而半纤维素损失仍然较低。最佳脱乙酰化条件为40°C、6小时和4 wt%的碳酸钠，导致玉米秸秆中80.55%的乙酰基被去除，半纤维素损失为4.09%。酸预水解产物中的乙酸浓度从1.38 g/L降至0.34 g/L。预处理后固体玉米秸秆和全浆料的酶解率分别提高了17%和16%。
