白蟻能大量吞吃木頭,，給家具帶來災(zāi)難性破壞，但美國普渡大學(xué)和佛羅里達大學(xué)的最新研究發(fā)現(xiàn),，它們的這種能力也可能為汽車帶來清潔燃料,。據(jù)美國物理學(xué)家組織網(wǎng)7月5日報道，研究人員在白蟻消化道發(fā)現(xiàn)了一種可把木頭分解成糖的混合酶,，有助于克服目前將木材轉(zhuǎn)化為生物燃料過程中存在的障礙,。
植物中的木質(zhì)素是木材分解成糖的最大障礙，而糖是生產(chǎn)生物燃料的基本成分,。木質(zhì)素是構(gòu)成植物細胞壁的最堅硬的部分,，封鎖了生物質(zhì)中的糖。“我們發(fā)現(xiàn)白蟻腸消耗系統(tǒng)中有一種混合酶,，能把木頭分解成糖,。”領(lǐng)導(dǎo)該研究的弗羅里達大學(xué)昆蟲與線蟲學(xué)系麥克·斯卡福說。
研究人員發(fā)現(xiàn),，不僅白蟻自身消化道能產(chǎn)生分解木材的酶,，在白蟻腸道中還有一種微小的共生生物（一種原生動物），也能產(chǎn)生某種酶,，協(xié)同幫助白蟻消化木材,。他們分離出了白蟻的腸道，并把樣本分成含有共生生物和不含共生生物的,，分別放在鋸末上,，然后對二者的產(chǎn)糖量進行了檢測。實驗結(jié)果表明,，有3種功能不同的酶,，能分解不同生物質(zhì)，其中兩種能釋放葡萄糖和戊糖,，另一種能分解木質(zhì)素,。
斯卡福說：“長期以來，人們認為共生生物僅僅是幫助消化,，其實共生的功能還有很多,。我們的實驗證明，宿主產(chǎn)生了某種酶,，與共生生物產(chǎn)生的酶結(jié)合起來發(fā)揮了更大作用,。宿主酶加共生生物酶的效果，就好比是1+1=4,。”
來自白蟻和它們共生生物的酶能有效克服木質(zhì)素轉(zhuǎn)化成糖的障礙,。將制造這些酶的基因插入病毒中喂給毛蟲，就能產(chǎn)出大量的酶,。實驗顯示,，人工合成的宿主白蟻酶在分解木質(zhì)釋放糖分方面很有效。人們可以把宿主白蟻作為產(chǎn)出酶源的主要部分,，用來生產(chǎn)生物燃料,。
斯卡福表示,，下一步他們將識別共生生物產(chǎn)生的酶，跟宿主白蟻酶結(jié)合,，讓木材能產(chǎn)出更多的糖以提高生物燃料的產(chǎn)量,。他的研究小組計劃與馬里蘭州的切薩皮克·皮爾蛋白產(chǎn)品公司合作，生產(chǎn)人工合成酶,。（生物谷Bioon.com）
生物谷推薦原文出處：
PLOS ONE doi:10.1371/journal.pone.0021709
Multiple Levels of Synergistic Collaboration in Termite Lignocellulose Digestion
Michael E. Scharf, Zachary J. Karl, Amit Sethi, Drion G. Boucias
In addition to evolving eusocial lifestyles, two equally fascinating aspects of termite biology are their mutualistic relationships with gut symbionts and their use of lignocellulose as a primary nutrition source. Termites are also considered excellent model systems for studying the production of bioethanol and renewable bioenergy from 2nd generation (non-food) feedstocks. While the idea that gut symbionts are the sole contributors to termite lignocellulose digestion has remained popular and compelling, in recent years host contributions to the digestion process have become increasingly apparent. However, the degree to which host and symbiont, and host enzymes, collaborate in lignocellulose digestion remain poorly understood. Also, how digestive enzymes specifically collaborate (i.e., in additive or synergistic ways) is largely unknown. In the present study we undertook translational-genomic studies to gain unprecedented insights into digestion by the lower termite Reticulitermes flavipes and its symbiotic gut flora. We used a combination of native gut tissue preparations and recombinant enzymes derived from the host gut transcriptome to identify synergistic collaborations between host and symbiont, and also among enzymes produced exclusively by the host termite. Our findings provide important new evidence of synergistic collaboration among enzymes in the release of fermentable monosaccharides from wood lignocellulose. These monosaccharides (glucose and pentoses) are highly relevant to 2nd-generation bioethanol production. We also show that, although significant digestion capabilities occur in host termite tissues, catalytic tradeoffs exist that apparently favor mutualism with symbiotic lignocellulose-digesting microbes. These findings contribute important new insights towards the development of termite-derived biofuel processing biotechnologies and shed new light on selective forces that likely favored symbiosis and, subsequently, group living in primitive termites and their cockroach ancestors.
