Department of Biotechnology, School of Marine, Fisheries and Life Science, Pukyong National University, Busan, 48513, Republic of Korea.
Jeju Marine Research Center, Korea Institute of Ocean Science and Technology (KIOST), Jeju, 63349, Republic of Korea.
Bioprocess Biosyst Eng. 2023 Jun;46(6):839-850. doi: 10.1007/s00449-023-02868-3. Epub 2023 Apr 1.
Eucheuma denticulatum is a red macroalgae with a high carbohydrate content. The fermentable sugars from E. denticulatum were obtained through sequential thermal acid hydrolysis, enzymatic saccharification, and detoxification. Thermal acid hydrolysis of E. denticulatum was optimized under the condition of 10% (w/v) slurry content and 300 mM HNO at 121 ℃ for 90 min. The maximum monosaccharide concentration after thermal acid hydrolysis was 31.0 g/L with an efficiency (E) of 44.7%. By further enzymatic hydrolysis of pretreated biomass solution under 20 U/mL Cellic CTec2 at 50 ℃ and 160 rpm for 72 h, the maximum monosaccharide concentration reached 79.9 g/L with an efficiency of 66.2% (E). To remove 5-hydroxymethylfurfural (5-HMF), a fermentation inhibitor, absorption using 2% activated carbon was performed for 2 min. Ethanol fermentation was performed using wild-type and high galactose-adapted strains of Saccharomyces cerevisiae, Kluyveromyces marxianus, and Candida lusitaniae. As a result, galactose-adapted strains showed higher ethanol production than wild-type strains. Especially, the fermentation result by adaptively evolved S. cerevisiae produced the highest ethanol of 37.6 g/L and with Y of 0.48 g/g. Moreover, the transcript level of MIG1 in the galactose-adapted strain was slightly lower than that in the wild-type strain. The application of adaptive evolution of microorganisms was efficient for bioethanol production.
鹿角菜是一种碳水化合物含量较高的红色大型藻类。通过顺序热酸水解、酶解和解毒，可以从鹿角菜中获得可发酵糖。在 10%（w/v）浆液含量和 300 mM HNO 在 121°C 下 90 分钟的条件下优化了鹿角菜的热酸水解。热酸水解后最大单糖浓度为 31.0 g/L，效率（E）为 44.7%。通过在 50°C 和 160 rpm 下用 20 U/mL Cellic CTec2 进一步酶解预处理生物质溶液 72 小时，最大单糖浓度达到 79.9 g/L，效率为 66.2%（E）。为了去除发酵抑制剂 5-羟甲基糠醛（5-HMF），使用 2%活性炭进行了 2 分钟的吸附。使用野生型和高半乳糖适应型酿酒酵母、马克斯克鲁维酵母和葡萄牙假丝酵母进行乙醇发酵。结果表明，半乳糖适应型菌株的乙醇产量高于野生型菌株。特别是，适应性进化的酿酒酵母的发酵结果产生了最高的 37.6 g/L 乙醇和 0.48 g/g 的 Y。此外，半乳糖适应型菌株中 MIG1 的转录水平略低于野生型菌株。微生物适应性进化的应用对生物乙醇生产是有效的。
