Department of Biotechnology, Pukyong National University, Busan, 48513, Republic of Korea.
J Environ Manage. 2021 Sep 1;293:112919. doi: 10.1016/j.jenvman.2021.112919. Epub 2021 Jun 2.
Microalgae are known as renewable, potential, and sustainable feedstocks for biofuel production. The present work investigated the efficient valorization of green microalgae Chlorella sp. to produce sugars and 5-hydroxymethylfurfural (5-HMF) using thermochemical conversion with a metal-salt (ferric sulfate) as catalyst using a statistical approach and two-step conversion. A statistical approach with a Box-Behnken design was introduced to optimize the conversion for producing sugars. As a result of optimization, 86.46% sugar yield (68.32% glucose yield) was achieved under the condition of 5% biomass and 0.6 g-catalyst/g-biomass at 155 °C and 40 min. Two-step thermochemical conversion was introduced to produce 5-HMF from microalgae. In the first step, sugars were produced from the above optimum condition; in the second step, sugar hydrolysates were converted into 5-HMF by thermochemical conversion without an additional catalyst. In two-step conversion, the maximum 5-HMF yield (37.23%) was achieved at 170 °C and 60 min from the sugar hydrolysate of microalgae obtained from the first-step thermochemical conversion with ferric sulfate. In conclusion, the microalgae as biomass and ferric sulfate as catalyst have availability and the potential to produce biosugars and platform chemicals.
微藻被认为是可再生、有潜力和可持续的生物燃料生产原料。本工作研究了利用热化学转化法，以金属盐（硫酸铁）为催化剂，通过统计方法和两步转化，高效利用绿色微藻小球藻生产糖和 5-羟甲基糠醛（5-HMF）。采用 Box-Behnken 设计的统计方法对生产糖的转化进行了优化。优化结果表明，在 5%生物质和 0.6 g-催化剂/g-生物质条件下，于 155°C 反应 40 min，可获得 86.46%的糖产率（68.32%葡萄糖产率）。引入两步热化学转化法从微藻生产 5-HMF。在第一步中，从上述最佳条件下生产糖；在第二步中，无需额外催化剂，通过热化学转化将糖水解产物转化为 5-HMF。在两步转化中，从硫酸铁进行的第一步热化学转化获得的糖水解产物在 170°C 和 60 min 时可获得最大的 5-HMF 产率（37.23%）。总之，微藻作为生物质和硫酸铁作为催化剂具有生产生物糖和平台化学品的可用性和潜力。
