Krolicka Malgorzata, Hinz Sandra W A, Koetsier Martijn J, Joosten Rob, Eggink Gerrit, van den Broek Lambertus A M, Boeriu Carmen G
Department of Bioprocess Engineering, Wageningen University , Wageningen, The Netherlands.
DuPont Industrial Biosciences , Wageningen, The Netherlands.
J Agric Food Chem. 2018 Feb 21;66(7):1658-1669. doi: 10.1021/acs.jafc.7b04032. Epub 2018 Feb 7.
A thermostable Chitinase Chi1 from Myceliophthora thermophila C1 was homologously produced and characterized. Chitinase Chi1 shows high thermostability at 40 °C (>140 h 90% activity), 50 °C (>168 h 90% activity), and 55 °C (half-life 48 h). Chitinase Chi1 has broad substrate specificity and converts chitin, chitosan, modified chitosan, and chitin oligosaccharides. The activity of Chitinase Chi1 is strongly affected by the degree of deacetylation (DDA), molecular weight (Mw), and side chain modification of chitosan. Chitinase Chi1 releases mainly (GlcNAc) from insoluble chitin and chito-oligosaccharides with a polymerization degree (DP) ranging from 2 to 12 from chitosan, in a processive way. Chitinase Chi1 shows higher activity toward chitin oligosaccharides (GlcNAc) than toward (GlcNAc) and is inactive for (GlcNAc). During hydrolysis, oligosaccharides bind at subsites -2 to +2 in the enzyme's active site. Chitinase Chi1 can be used for chitin valorisation and for production of chitin- and chito-oligosaccharides at industrial scale.
嗜热毁丝霉C1中一种耐热几丁质酶Chi1被同源表达并进行了表征。几丁质酶Chi1在40℃（>140小时保持90%活性）、50℃（>168小时保持90%活性）和55℃（半衰期48小时）下显示出高耐热性。几丁质酶Chi1具有广泛的底物特异性，可作用于几丁质、壳聚糖、改性壳聚糖和几丁质寡糖。几丁质酶Chi1的活性受壳聚糖的脱乙酰度（DDA）、分子量（Mw）和侧链修饰的强烈影响。几丁质酶Chi1主要从不溶性几丁质中释放（N-乙酰葡糖胺），并以连续方式从壳聚糖中释放聚合度（DP）为2至12的几丁质寡糖。几丁质酶Chi1对几丁质寡糖（N-乙酰葡糖胺）的活性高于对（N-乙酰葡糖胺）的活性，对（N-乙酰葡糖胺）无活性。在水解过程中，寡糖结合在酶活性位点的-2至+2亚位点。几丁质酶Chi1可用于几丁质的增值利用以及工业规模生产几丁质和几丁质寡糖。
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