堿性果膠酶（EC：4.2.2.2）是一類在堿性條件下,，以反式消去作用斷開果膠質(zhì)主鏈,，產(chǎn)生不飽和的寡聚半乳糖醛酸的酶，在紡織工業(yè)的麻類脫膠,、棉織品精煉等領(lǐng)域內(nèi)有著廣泛的應(yīng)用,。相比于傳統(tǒng)的高堿、高溫處理手段,，使用堿性果膠酶不僅對(duì)果膠質(zhì)有較好的去除作用,，對(duì)天然纖維素纖維損傷較小，而且可以減少材料消耗和環(huán)境負(fù)擔(dān),，為紡織工業(yè)開辟了一條綠色清潔之路,。
中科院天津工業(yè)生物技術(shù)研究所結(jié)構(gòu)生物信息學(xué)與整合系統(tǒng)生物學(xué)課題組針對(duì)如何實(shí)現(xiàn)果膠裂解酶工業(yè)化高產(chǎn)這一關(guān)鍵環(huán)節(jié)，開展了一系列的工作,。本工作使用簡(jiǎn)并PCR的方法,，從環(huán)境基因組中挖掘到一條新型果膠裂解酶序列，并在大腸桿菌中實(shí)現(xiàn)了表達(dá),。通過對(duì)其酶學(xué)性質(zhì)的研究和麻類脫膠效果的評(píng)估,，發(fā)現(xiàn)該酶具有很大的實(shí)際應(yīng)用潛力。本工作又進(jìn)一步使用高細(xì)胞密度發(fā)酵優(yōu)化方法,，實(shí)現(xiàn)了果膠裂解酶在大腸桿菌中的高產(chǎn),，在7L發(fā)酵罐上產(chǎn)量可達(dá)1816.2 U/mL，遠(yuǎn)高于同行報(bào)道的水平,，有利于工業(yè)化大生產(chǎn)的應(yīng)用,，提高了我國(guó)在重要工業(yè)酶的發(fā)酵生產(chǎn)和紡織工業(yè)清潔化生產(chǎn)等關(guān)鍵技術(shù)領(lǐng)域的研究水平。
該研究得到中國(guó)科學(xué)院“百人計(jì)劃”及知識(shí)創(chuàng)新項(xiàng)目（KSCX2-EW-G-8）和天津市重大科技攻關(guān)項(xiàng)目（10ZCKFSY05600）的資助,，申請(qǐng)并獲得國(guó)家授權(quán)專利1項(xiàng)（ZL 2012 1 0064448.0）,。
最新研究結(jié)果發(fā)表在 Process Biochemistry 雜志上，天津工業(yè)生物所結(jié)構(gòu)生物信息學(xué)與整合系統(tǒng)生物學(xué)課題組科研助理王輝林和李小曼為論文的共同第一作者,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Process Biochemistry doi.org/10.1016/j.procbio.2013.10.001
Characterization and high-level expression of a metagenome-derived alkaline pectate lyase in recombinant Escherichia coli
Huilin Wanga， 1,， Xiaoman Lia,， 1， Yanhe Maa,， b,， Jiangning Songa,， c
Alkaline pectate lyases (PLs) play an important role in mild and eco-friendly bioscouring pretreatment processes in the textile industry. However， to date,， only a few PLs can be applied in industrial-scale production,， and many of them exhibit high production cost， low activity,， and/or do not meet the treatment requirements. In this study,， an alkaline PL gene was cloned from the metagenomic DNA of alkaline environment soils. The gene pelB consisted of 1263 nucleotides and encoded a mature protein (PelB) of 399 amino acids， which was expressed in Escherichia coli. The maximum catalytic activity of the enzyme exhibited a bimodal distribution at pH 8.1 and 9.8 and an optimal temperature of 55 °C. The Km and Vmax values of PelB were 1.78 g/L and 1084.8 μmol/(L min) at 45 °C,， respectively. Substrate specificity analysis demonstrated the high cleavage capability of PelB on a broad range of substrates of natural methylated pectin. Based on the degradation products,， PelB was considered to be an endo-acting lyase. Using high-cell-density cultivation in 7-L bioreactor， the highest PL activity (1816.2 U/mL) was achieved. Thus,， the recombinant PelB,， with promising properties for use in bioscouring in the textile pretreatment process， should be a potential enzyme for industrial applications.
