美国科学家近日发现，热带白蚁体内微生物分泌的酶可将植物纤维素转化为糖类，而这些糖类在发酵后能够成为生物燃料。这意味着人们在清洁、可再生燃料的探所上再进一步。
据法新社报道，美国一个研究小组日前在英国《自然》杂志上发表论文说，中非一种白蚁的后肠中“可能藏有微生物金矿”，这些微生物能分泌出酶，使白蚁顺利分解食入的木材纤维，将木聚合物转化为糖类，从而获得营养。
研究人员表示，这种藏身于白蚁下半身的酶十分宝贵，可以用来制造新一代生物燃料，替代有污染、价格昂贵并带来地缘政治风险的化石燃料。
目前，研究小组正在将一部分微生物的遗传密码进行排序和分析，希望仿照白蚁的微型生物反应器进行工业生产。
据报道，目前人们所使用的生物燃料主要来自玉米和蔗糖等作物，原理是利用酶、发酵和蒸馏等方式使作物中的淀粉转化为乙醇。新一代生物燃料将使用粮食以外的植物纤维素材料，如木屑和稻草；但是，碍于成本和复杂性，这些新的加工方法很难实现大规模生产。（新华网）
原始出处:
Nature 450, 560-565 (22 November 2007) | doi:10.1038/nature06269; Received 15 July 2007; Accepted 18 September 2007
Metagenomic and functional analysis of hindgut microbiota of a wood-feeding higher termite
Falk Warnecke1,8, Peter Luginbühl2,8, Natalia Ivanova1, Majid Ghassemian2, Toby H. Richardson2,9, Justin T. Stege2, Michelle Cayouette2, Alice C. McHardy3,9, Gordana Djordjevic2, Nahla Aboushadi2, Rotem Sorek1, Susannah G. Tringe1, Mircea Podar4, Hector Garcia Martin1, Victor Kunin1, Daniel Dalevi1, Julita Madejska1, Edward Kirton1, Darren Platt1, Ernest Szeto1, Asaf Salamov1, Kerrie Barry1, Natalia Mikhailova1, Nikos C. Kyrpides1, Eric G. Matson5, Elizabeth A. Ottesen6, Xinning Zhang5, Myriam Hernández7, Catalina Murillo7, Luis G. Acosta7, Isidore Rigoutsos3, Giselle Tamayo7, Brian D. Green2, Cathy Chang2, Edward M. Rubin1, Eric J. Mathur2,9, Dan E. Robertson2, Philip Hugenholtz1 & Jared R. Leadbetter5,8
DOE Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, California 94598, USA
Verenium Corporation (formerly Diversa), 4955 Directors Place, San Diego, California 92121, USA
IBM Thomas J. Watson Research Center, PO Box 218, Yorktown Heights, New York 10598, USA
Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, Tennessee 37831-6026, USA
Department of Environmental Science and Engineering,
Division of Biology, Mailcode 138-78, California Institute of Technology, Pasadena, California 91125, USA
INBio, Instituto Nacional de Biodiversidad, Apdo. Postal 22-3100 Santo Domingo de Heredia, Costa Rica
These authors contributed equally to this work.
Present addresses: Synthetic Genomics, Inc., 11149 North Torrey Pines Road, Suite 100, La Jolla, California 92037, USA (T.H.R., E.J.M.); Max Planck Institute for Computer Science, Stuhlsatzenhausweg 85, 66123 Saarbrücken, Germany (A.C.M.).
Correspondence to: Jared R. Leadbetter5,8 Correspondence and requests for materials should be addressed to J.R.L. (Email: jleadbetter@caltech.edu).
From the standpoints of both basic research and biotechnology, there is considerable interest in reaching a clearer understanding of the diversity of biological mechanisms employed during lignocellulose degradation. Globally, termites are an extremely successful group of wood-degrading organisms1 and are therefore important both for their roles in carbon turnover in the environment and as potential sources of biochemical catalysts for efforts aimed at converting wood into biofuels. Only recently have data supported any direct role for the symbiotic bacteria in the gut of the termite in cellulose and xylan hydrolysis2. Here we use a metagenomic analysis of the bacterial community resident in the hindgut paunch of a wood-feeding 'higher' Nasutitermes species (which do not contain cellulose-fermenting protozoa) to show the presence of a large, diverse set of bacterial genes for cellulose and xylan hydrolysis. Many of these genes were expressed in vivo or had cellulase activity in vitro, and further analyses implicate spirochete and fibrobacter species in gut lignocellulose degradation. New insights into other important symbiotic functions including H2 metabolism, CO2-reductive acetogenesis and N2 fixation are also provided by this first system-wide gene analysis of a microbial community specialized towards plant lignocellulose degradation. Our results underscore how complex even a 1-l environment can be.
