College of Life Science and Agriculture Forestry, Qiqihar University, Qiqihar, 161006, China.
Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
BMC Biotechnol. 2024 Jan 10;24(1):2. doi: 10.1186/s12896-023-00826-1.
Lytic polysaccharide monooxygenases (LPMOs) catalyzing the oxidative cleavage of different types of polysaccharides have potential to be used in various industries. However, AA13 family LPMOs which specifically catalyze starch substrates have relatively less members than AA9 and AA10 families to limit their application range. Amylase has been used in enzymatic desizing treatment of cotton fabric for semicentury which urgently need for new assistant enzymes to improve reaction efficiency and reduce cost so as to promote their application in the textile industry.
A total of 380 unannotated new genes which probably encode AA13 family LPMOs were discovered by the Hidden Markov model scanning in this study. Ten of them have been successfully heterologous overexpressed. AlLPMO13 with the highest activity has been purified and determined its optimum pH and temperature as pH 5.0 and 50 °C. It also showed various oxidative activities on different substrates (modified corn starch > amylose > amylopectin > corn starch). The results of enzymatic textile desizing application showed that the best combination of amylase (5 g/L), AlLPMO13 (5 mg/L), and HO (3 g/L) made the desizing level and the capillary effects increased by 3 grades and more than 20%, respectively, compared with the results treated by only amylase.
The Hidden Markov model constructed basing on 34 AA13 family LPMOs was proved to be a valid bioinformatics tool for discovering novel starch-active LPMOs. The novel enzyme AlLPMO13 has strong development potential in the enzymatic textile industry both concerning on economy and on application effect.
氧化脱糖酶（LPMOs）能够催化不同类型多糖的氧化裂解，具有在各个行业中应用的潜力。然而，特异性催化淀粉底物的 AA13 家族 LPMOs 的成员相对较少，限制了其应用范围。淀粉酶已在棉织物的酶退浆处理中使用了半个世纪，因此迫切需要新的辅助酶来提高反应效率和降低成本，从而促进其在纺织工业中的应用。
通过本研究中的隐马尔可夫模型扫描，共发现了 380 个可能编码 AA13 家族 LPMOs 的未注释的新基因。其中 10 个已成功异源过表达。具有最高活性的 AlLPMO13 已被纯化，并确定其最适 pH 和温度分别为 pH5.0 和 50°C。它还对不同底物（改性玉米淀粉>直链淀粉>支链淀粉>玉米淀粉）表现出各种氧化活性。酶法纺织品退浆应用结果表明，与仅用淀粉酶处理的结果相比，淀粉酶（5 g/L）、AlLPMO13（5 mg/L）和 HO（3 g/L）的最佳组合使退浆水平和毛细效应分别提高了 3 级和 20%以上。
基于 34 个 AA13 家族 LPMOs 构建的隐马尔可夫模型被证明是发现新型淀粉活性 LPMOs 的有效生物信息学工具。新型酶 AlLPMO13 在酶法纺织品工业中具有很强的发展潜力，无论是在经济性还是应用效果方面。
