产红青霉菌对脲醛树脂的降解机制  

Degradation mechanism of Penicillium rubens 23229 on urea-formaldehyde resin

作　　者：郭仕伟 向阳 仝迎芳 刘亚青 郭建峰[1] 白玉洁[1] 高焕 秦旭巍 王芳[1,2] Guo Shiwei;Xiang Yang;Tong Yingfang;Liu Yaqing;Guo Jianfeng;Bai Yujie;Gao Huan;Qin Xuwei;Wang Fang(School of Chemistry and Chemical Engineering,North University of China,Taiyuan 030051,China;Shanxi Province Key Laboratory of Functional Nanocomposites,School of Materials Science and Engineering,North University of China,Taiyuan 030051 China;Research Center for Engineering Technology of Polymeric Composites of Shanxi Province,North University of China,Taiyuan,030051 China)

机构地区：[1]中北大学化学与化工学院,山西太原030051 [2]纳米功能复合材料山西省重点实验室,山西太原030051 [3]山西省高分子复合材料工程技术研究中心,山西太原030051

出　　处：《山西农业大学学报（自然科学版）》2024年第3期99-107,共9页Journal of Shanxi Agricultural University(Natural Science Edition)

基　　金：中央引导地方科技发展资金项目(YDZJSX2021B007);山西省重点研发计划项目(202302040201007);纳米功能复合材料山西省重点实验室开放基金(NFCM202003);山西省农业农村领域“六新”项目;山西省高分子缓控释肥料重点研发中心。

摘　　要：[目的]每年有30多万吨脲醛用做树脂、粘合剂和绝缘材料,由于其降解持久性,此类物质废弃后对环境造成广泛的损害。本研究以产红青霉菌(Penicillium rubens 23229)为对象,研究其对脲醛树脂(UF)的降解过程和降解酶的性质。[方法]用X-射线衍射(XRD)和失重率评价P.rubens 23229及其酶的降解能力,通过液相-质谱联用(LC-MS)分析降解过程中间代谢产物,应用凝胶色谱柱对降解酶进行纯化。[结果]P.rubens 23229作用于UF,30 d后,材料失重率(降解率)为35%,结晶度由26.21%提升至29.44%,经计算得出,降解的35%包括UF结晶区7%,非结晶区28%;从菌种和脲醛共培养液中得到P.rubens 23229脲醛降解粗酶液,其最适作用温度为50℃,最适pH为4.0,LC-MS结果表明该粗酶液在降解过程中,首先将高分子UF主链降解,形成四甲基五脲、三甲基四脲等短链中间代谢物,然后进一步分解中间代谢产物为二氧化碳以及甲醛等终产物,降解作用位点包括脲醛主链中亚甲基与尿素间的C-N、酰胺键等。进一步对比了P.rubens 23229粗酶液与商业脲酶、蛋白酶对UF的降解能力,发现蛋白酶几乎无降解效果,脲酶有一定降解能力,但显著低于P.rubens 23229粗酶液。粗酶经纯化后降解效率提高28倍,凝胶渗透色谱(GPC)显示出分子量为6.89 kD和220.83 kD的2个峰,对应前面降解过程分析,说明降解过程包含主链降解酶和中间代谢物降解酶至少2种酶的复合体系共同发挥作用。[结论]P.rubens 23229脲醛降解酶由主链降解酶和中间代谢物降解酶共同组成,其中包含脲酶作用类似的酶,但降解主链的酶与已有蛋白酶作用方式不同,其具体的组成与性质有待于进一步研究。本研究对UF的生物降解具有一定的参考价值。[Objective]More than 300000 tons of urea-formaldehyde resin(UF)are used annually as resins,adhesives,and in-sulating materials,resulting in extensive environmental damage when discarded due to their persistent degradation.In this study,Penicillium rubens 23229(P.rubens 23229)was used to investigate the degradation process of UF and the properties of degradation enzymes.[Methods]The degradation ability of P.rubens 23229 and its enzyme were evaluated by X-ray diffraction(XRD)and UF weight loss analysis.The intermediate metabolites were analyzed by liquid-phase mass spectrometry(LC-MS),while the enzyme was purified by a gel permeation chromatography.[Results]After being co-cultured with P.rubens 23229 for 30 days,UF material experienced a mass loss(degradation rate)of 35%,and the crystallinity increased from 26.21%to 29.44%.Based on analysis and calculation,it was determined that the degraded 35%of UF consist of 7%in the crystalline zone and 28%in the non-crystalline zone.The characters of the crude enzyme liquid,which was isolated from the co-culture medium of P.rubens 23229 and UF were determined,and the optimal temperature was 50℃,the optimal pH was 4.0.The LC-MS results showed that the crude enzyme liquid initially degraded the main chain of the UF and formed short chain intermediate metabolites such as tetramethylpentaurea and trimethyltetramethyltetrourea during the degradation process.Then the intermediate metabolites were further decomposed into end products such as carbon dioxide and formaldehyde,with degradation sites including C-N and amide bonds between methylidene and urea in the main chain of UF.The degradation abili-ty of the P.rubens 23229 crude enzyme solution on UF was further compared with that of commercial urease and protease.It was found that the protease had almost no degradation effect;while urease had a certain degradation ability,but it was signifi-cantly lower than that of the P.rubens 23229 crude enzyme solution.After purification,the degradation efficiency of the crude enzyme was incre

关 键 词：脲醛树脂 P.rubens 23229 脲醛降解酶 生物降解 

分 类 号：Q89[生物学] Q939.96