Wang Damao, Yun Eun Ju, Kim Sooah, Kim Do Hyoung, Seo Nari, An Hyun Joo, Kim Jae-Han, Cheong Nam Yong, Kim Kyoung Heon
Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, Republic of Korea.
Graduate School of Analytical Science and Technology, Asia-Pacific Glycomics Reference Site, Chungnam National University, Daejeon, 34134, Republic of Korea.
Bioprocess Biosyst Eng. 2016 Jun;39(6):959-66. doi: 10.1007/s00449-016-1575-z. Epub 2016 Feb 29.
This study was performed to evaluate the effectiveness of acidic pretreatment in increasing the enzymatic digestibility of alginate from brown macroalgae. Pretreatment with 1 % (w/v) sulfuric acid at 120 °C for 30 min produced oligosaccharides, mannuronic acid, and guluronic acid. Enzymatic saccharification of pretreated alginate by alginate lyases produced 52.2 % of the theoretical maximal sugar yield, which was only 7.5 % higher than the sugar yield obtained with unpretreated alginate. Mass spectrometric analyses of products of the two reactions revealed that acidic pretreatment and enzymatic saccharification produced saturated monomers (i.e., mannuronic and guluronic acid) with saturated oligosaccharides and unsaturated monomers (i.e., 4-deoxy-L-erythro-5-hexoseulose uronic acid; DEH), respectively. While DEH is further metabolized by microorganisms, mannuronic acid and guluronic acid are not metabolizable. Because of the poor efficacy in increasing enzymatic digestibility and owing to the formation of non-fermentable saturated monomers, acidic pretreatment cannot be recommended for enzymatic saccharification and fermentation of alginate.
本研究旨在评估酸性预处理对提高褐藻中藻酸盐酶解消化率的有效性。在120℃下用1%（w/v）硫酸预处理30分钟可产生低聚糖、甘露糖醛酸和古洛糖醛酸。用海藻酸裂解酶对预处理后的藻酸盐进行酶促糖化，得到的糖产量为理论最大糖产量的52.2%，仅比未预处理的藻酸盐获得的糖产量高7.5%。对两个反应产物的质谱分析表明，酸性预处理和酶促糖化分别产生了含有饱和低聚糖的饱和单体（即甘露糖醛酸和古洛糖醛酸）和不饱和单体（即4-脱氧-L-赤藓糖-5-己糖醛酸；DEH）。虽然DEH可被微生物进一步代谢，但甘露糖醛酸和古洛糖醛酸不可代谢。由于在提高酶解消化率方面效果不佳，且由于形成了不可发酵的饱和单体，因此不建议对藻酸盐进行酸性预处理以用于酶促糖化和发酵。
