Biosolutions to the energy problem

  • Arnold L. DemainEmail author


We are in an energy crisis caused by years of neglect to alternative energy sources. There are many possible solutions and a number of these are based on microorganisms. These include bioethanol, biobutanol, biodiesel, biohydrocarbons, methane, methanol, electricity-generating microbial fuel cells, and production of hydrogen via photosynthetic microbes. In this review, I will focus on the first four possibilities.


Ethanol Butanol Biodiesel Energy crisis Petroleum Microbial fermentations 



I thank Professor Lee R. Lynd of Dartmouth College for much advice over the years on this subject.


  1. 1.
    Allen SG, Schulman D, Lichwa J, Antal MJ, Jennings E, Elander R (2001) A comparison of aqueous and dilute-acid single-temperature pretreatment of yellow poplar sawdust. Ind Eng Chem Res 40:2352–2361. doi: 10.1021/ie000579+ Google Scholar
  2. 2.
    Atsumi S, Hanai T, Liao JC (2008) Non-fermentative pathways for synthesis of branched-chain higher alcohols as fuels. Nature 451:86–89. doi: 10.1038/nature06450 PubMedGoogle Scholar
  3. 3.
    Bayer EA, Lamed R (1986) Ultrastructure of the cell surface cellulosome of Clostridium thermocellum and its interaction with cellulose. J Bacteriol 167:828–836PubMedGoogle Scholar
  4. 4.
    Bayer EA, Kenig R, Lamed R (1983) Adherence of Clostridium thermocellum to cellulose. J Bacteriol 156:818–827PubMedGoogle Scholar
  5. 5.
    Bayer EA, Morag E, Lamed R (1994) The cellulosome—a treasure-trove for biotechnology. Trends Biotechnol 12:379–386. doi: 10.1016/0167-7799(94)90039-6 PubMedGoogle Scholar
  6. 6.
    Bayer EA, Setter E, Lamed R (1985) Organization and distribution of the cellulosome in Clostridium thermocellum. J Bacteriol 163:552–559PubMedGoogle Scholar
  7. 7.
    Bayer EA, Shimon LJW, Shoham Y, Lamed R (1998) Cellulosomes—structure and ultrastructure. J Struct Biol 124:221–234. doi: 10.1006/jsbi.1998.4065 PubMedGoogle Scholar
  8. 8.
    Beguin P, Aubert JP (1994) The biological degradation of cellulose. FEMS Microbiol Rev 13:25–58. doi: 10.1111/j.1574-6976.1994.tb00033.x PubMedGoogle Scholar
  9. 9.
    Beguin P, Lemaire M (1996) The cellulosome: an exocellular, mutiprotein complex specialized in cellulose degradation. Crit Rev Biochem Mol Biol 31:201–236. doi: 10.3109/10409239609106584 PubMedGoogle Scholar
  10. 10.
    Beguin P, Millet J, Aubert J-P (1992) Cellulose degradation by Clostridium thermocellum: from manure to molecular biology. FEMS Microbiol Lett 100:523–528. doi: 10.1111/j.1574-6968.1992.tb05750.x Google Scholar
  11. 11.
    BioCycle eNews Bulletin (2005) Creating cellulosic ethanol: spinning straw into fuel by Diane Greer. (http//
  12. 12.
    Blanch HW, Adams PD, Andrews-Cramer KM, Frommer WB, Simmons BA, Keasling JD (2008) Addressing the need for alternative transportation fuels: the joint bioenergy institute. ACS Chem Biol 3:17–20. doi: 10.1021/cb700267s PubMedGoogle Scholar
  13. 13.
    Bothast R, Schlicher MA (2005) Biotechnological processes for conversion of corn into ethanol. Appl Microbiol Biotechnol 67:19–25. doi: 10.1007/s00253-004-1819-8 PubMedGoogle Scholar
  14. 14.
    Bothast R, Nichols NN, Dien BS (1999) Fermentations with new recombinant organisms. Biotechnol Prog 75:867–875. doi: 10.1021/bp990087w Google Scholar
  15. 15.
    Bumazkin BK, Velikodsorsakaya GA, Tuka K, Mogutov MA, Strongin A (1990) Cloning of Clostridium thermocellum endoglucanase genes in Escherichia coli. Biochem Biophys Res Commun 168:1326–1327Google Scholar
  16. 16.
    Chisti Y (2008) Biodiesel from micralgae beats bioethanol. Trends Biotechnol 26:126–131. doi: 10.1016/j.tibtech.2007.12.002 PubMedGoogle Scholar
  17. 17.
    Collyer DM, Fogg GE (1955) Studies on fat accumulation by algae. J Exp Bot 6:227–256. doi: 10.1093/jxb/6.2.256 Google Scholar
  18. 18.
    Demain AL (2006) The crucial importance of bioethanol and the contribution of anaerobic bacteria and cellulosomes. In: Uversky V, Kataeva IA (eds) Cellulosome. Nova Science Publishers Incorporation, New York, pp 1–9Google Scholar
  19. 19.
    Demain AL, Wu JHD (1989) The cellulase complex of Clostridium thermocellum. In: Ghose TK (ed) First generation of bioprocess engineering. Ellis Horwood, Chichester, pp 68–86Google Scholar
  20. 20.
    Demain AL, Lynd LR (1994) Turning garbage into motor fuel: fanciful dream or feasible scheme? In: Shimada K, Hoshino S, Ohmiya K, Sakka K, Kobayashi Y, Karita S (eds) Genetics, biochemistry and ecology of lignocellulose degradation. Uni Publ Co Ltd, Tokyo, pp 573–583Google Scholar
  21. 21.
    Demain AL, Newcomb M, Wu JHD (2005) Cellulase, clostridia and ethanol. Microbiol Mol Biol Rev 69:124–154. doi: 10.1128/MMBR.69.1.124-154.2005 PubMedGoogle Scholar
  22. 22.
    Demain A, Klapatch TR, Jung KH, Lynd LR (1996) Recombinant DNA technology in development of an economical conversion of waste to liquid fuel. Ann N Y Acad Sci 782:402–412. doi: 10.1111/j.1749-6632.1996.tb40578.x Google Scholar
  23. 23.
    Desai SG, Guerinot ML, Lynd LR (2004) Cloning of the l-lactate dehydrogenase gene and elimination of lactic acid production via gene knockout in Thermoanerobacterium saccharolyticum JW/SL-YS485. Appl Microbiol Biotechnol 65:600–605. doi: 10.1007/s00253-004-1575-9 PubMedGoogle Scholar
  24. 24.
    Dien BS, Nichols NN, O’Bryan PJ, Bothast RJ (2000) Development of new ethanologenic Escherichia coli strains for fermentation of lignocellulosic biomass. Appl Biochem Biotechnol 84–86:181–196. doi: 10.1385/ABAB:84-86:1-9:181 PubMedGoogle Scholar
  25. 25.
    DOE report (2005) Genomics: GTL roadmap: systems biology for energy and environment. US Department of Energy Office of Science, p 298. (
  26. 26.
    DOE and Argon Labs report (2005) Ethanol study. DOE office of energy efficiency and renewable energy. (
  27. 27.
    DOE report (2006) Breaking the biological barriers to cellulosic ethanol: a joint research agenda. A research roadmap resulting from the biomass to biofuel workshop, 7–9 December 2005 at Rockville. US Department of Energy. Office of science and office of energy efficiency and renewable energy. (
  28. 28.
    Doran JB, Ingram LO (1993) Fermentation of crystalline cellulose to ethanol by Klebsiella oxytoca containing chromosomaaly integrated Zymomonas mobilis genes. Biotechnol Prog 9:533–538Google Scholar
  29. 29.
    El-Gogary S, Leite A, Crivellaro O, Eveleigh DE, El-Dorry H (1989) Mechanism by which cellulose triggers cellobiohydrolase I gene expression in Trichoderma reesei. Proc Natl Acad Sci USA 86:6138–6141PubMedGoogle Scholar
  30. 30.
    Ezeji TC, Qureshi N, Blaschek HP (2007) Production of acetone butanol (AB) from liquefied corn starch, a commercial substrate, using Clostridium beijerinckii coupled with product recovery by gas stripping. J Ind Microbiol Biotechnol 34:771–777PubMedGoogle Scholar
  31. 31.
    Farrell AE, Plevin RJ, Turner BT, Jones AD, O’Hare M, Kammen DM (2006) Ethanol can contribute to energy and environmental goals. Science 311:506–508PubMedGoogle Scholar
  32. 32.
    Felix CR, Ljungdahl LG (1993) The cellulosome: the extracellular organelle of Clostridium. Annu Rev Microbiol 47:791–819PubMedGoogle Scholar
  33. 33.
    Fox JL (2002) Legislation, technology boosting renewable fuel, materials uses. ASM News 68:480–481Google Scholar
  34. 34.
    Galbe M, Zacchi G (2002) A review of the production of ethanol from softwood. Appl Microbiol Biotechnol 59:618–628PubMedGoogle Scholar
  35. 35.
    Garcia-Martinez DV, Shinmyo A, Madia A, Demain AL (1980) Studies on cellulase production by Clostridium thermocellum. Eur J Appl Microbiol Biotechnol 9:189–197Google Scholar
  36. 36.
    Georgieva T, Mikkelsen M, Ahring B (2007) High ethanol tolerance of the thermophilic anaerobic ethanol producer Thermoanaerobacter BG1L1. Cent Eur J Biol 2:364–377Google Scholar
  37. 37.
    Georgieva TI, Ahring BK (2007) Evaluation of continuous ethanol fermentation of dilute-acid corn stover hydrolysate using thermophilic anaerobic bacterium Thermoanaerobacter BG1L1. Appl Microbiol Biotechnol 77:61–68PubMedGoogle Scholar
  38. 38.
    Gerngross UT, Romaniec MPM, Huskisson NS, Demain AL (1993) Sequencing of a Clostridium thermocellum gene (cipA) encoding the cellulosomal SL-protein reveals an unusual degree of internal homology. Mol Microbiol 8:325–334PubMedGoogle Scholar
  39. 39.
    Gold ND, Martin VJJ (2007) Global view of the Clostridium thermocellum cellulosome revealed by quantitative proteomic analysis. J Bacteriol 189:6787–6795PubMedGoogle Scholar
  40. 40.
    Gorhmann K, Torget R, Himmel M (1985) Optimization of dilute acid pretreatment of biomass. Biotechnol Bioeng Symp 15:59–80Google Scholar
  41. 41.
    Gray KA, Zhao L, Emptage M (2006) Bioethanol. Curr Opin Chem Biol 10:141–146PubMedGoogle Scholar
  42. 42.
    Green D (2005) Spinning straw into fuel. Biocycle 46:61–65Google Scholar
  43. 43.
    Greene N, Roth R (2006) Ethanol: energy well spent. A review of corn and cellulosic energy balances in the scientific literature to date. Ind Biotechnol 2:36–39Google Scholar
  44. 44.
    Greene N et al (2004) Growing energy. How biofuels can help end America’s oil dependence. Natl Res Def Council Rept, New York, pp 1–94. (
  45. 45.
    Guimaraes BG, Soucho H, Lytle BL, Wu JHD, Alzari PM (2002) The crystal structure and catalytic mechanism of the cellobiohydrolase CelS, the major enzymatic component of the Clostridium thermocellum cellulosome. J Mol Biol 320:578–596Google Scholar
  46. 46.
    Hahn-Hägerdahl B, Karhumaa K, Fonseca C, Spencer-Martins I, Gorwa-Grauslund M (2007) Towards industrial pentose-fermenting yeast strains. Appl Microbiol Biotechnol 74:937–953Google Scholar
  47. 47.
    Hahn-Hägerdahl B, Pamment N (2004) Special session A: microbial pentose metabolism. Appl Biochem Biotechnol 113–116:1207–1209Google Scholar
  48. 48.
    Herrero AA, Gomez RF, Roberts MF (1985) 35P-NMR studies of Clostridium thermocellum. Mechanism of end product inhibition by ethanol. J Biol Chem 260:7442–7451PubMedGoogle Scholar
  49. 49.
    Hess G (2006) Bush promotes alternative fuel. Chem Eng News 84(10):50–56Google Scholar
  50. 50.
    Hess G (2006) Push for biofuels seen in farm bill. Chem Eng News 84(21):29–31Google Scholar
  51. 51.
    Hon-nami K, Coughlan MP, Hon-nami H, Ljungdahl LG (1986) Separation and characterization of the complexes constituting the cellulolytic enzyme system of Clostridium themocellum. Arch Microbiol 145:13–19Google Scholar
  52. 52.
    Irwin DC, Zhang S, Wilson DB (2000) Cloning, expression and characterization of a family 48 exocellulase, Cel48a, from Thermobifida fusca. Eur J Biochem 267:4988–4997PubMedGoogle Scholar
  53. 53.
    Jeffries TW (2005) Ethanol fermentation on the move. Nat Biotechnol 23:40–41PubMedGoogle Scholar
  54. 54.
    Jeffries TW et al (2007) Genome sequence of the lignocellulose-biocoverting and xylose-fermenting yeast Pichia stipitis. Nat Biotechnol 25:319–326PubMedGoogle Scholar
  55. 55.
    Johnson EA (1983) Regulation of cellulase activity and synthesis in Clostridium thermocellum. Ph.D. thesis, Massachusetts Institute of Technology, CambridgeGoogle Scholar
  56. 56.
    Johnson J (2006) Beyond corn: biomass to bioenergy. Chem Eng News 84(35):16Google Scholar
  57. 57.
    Kalscheuer R, Stölting T, Steinbüchel A (2006) Microdiesel: Escherichia coli engineered for fuel production. Microbiology 152:2529–2536PubMedGoogle Scholar
  58. 58.
    Keasling JD, Chou H (2008) Metabolic engineering delivers next-generation biofuels. Nat Biotechnol 26:298–299PubMedGoogle Scholar
  59. 59.
    Klapatch TR, Demain AL, Lynd LR (1996) Restriction endonuclease activity in Clostridium thermocellum and Clostridium thermosaccharoyuticum. Appl Microbiol Biotechnol 45:127–131PubMedGoogle Scholar
  60. 60.
    Klapatch TR, Guerinot ML, Lynd LR (1996) Electrotransformation of Clostridium thermosaccharoyuticum. J Ind Microbiol 16:342–347PubMedGoogle Scholar
  61. 61.
    Kong Q-X, Gu J-G, Cao L-M, Zhang A-L, Chen X, Zhao X-M (2006) Improved production of ethanol by deleting FPS1 and over-expressing GLT1 in Saccharomyces cerevisiae. Biotechnol Lett 28:2033–2038PubMedGoogle Scholar
  62. 62.
    Kong Q-X, Cao L-M, Zhang A-L, Chen X (2007) Overexpressing GLT1 in gpd1 Δ mutant to improve the production of ethanol of Saccharomyces cerevisiae. Appl Microbiol Biotechnol 73:1382–1386PubMedGoogle Scholar
  63. 63.
    Kruus K, Lua AC, Demain AL, Wu JHD (1995) The anchorage function of CipA (celL), a scaffolding protein of the Clostridium thermocellum cellulosome. Proc Natl Acad Sci USA 92:924–9258Google Scholar
  64. 64.
    Kruus K, Andreacchi A, Wang WK, Wu JHD (1995) Product inhibition of the recombinant CelS, an exoglucanase component of the Clostridium thermocellum cellulosome. Appl Microbiol Biotechnol 44:399–404PubMedGoogle Scholar
  65. 65.
    Lamed R, Bayer EA (1986) Contact and cellulolysis in Clostridium themocellum via extensile surface organelles. Experientia 42:72–73Google Scholar
  66. 66.
    Lamed R, Bayer EA (1988) The cellulosome of Clostridium thermocellum. Adv Appl Microbiol 33:1–46Google Scholar
  67. 67.
    Lamed R, Zeikus JG (1980) Ethanol production by thermophilic bacteria: relationship between fermentation product yields and catabolic enzyme activities in Clostridium thermocellum and Thermoanaerobium brockii. J Bacteriol 144:569–578PubMedGoogle Scholar
  68. 68.
    Lamed R, Setter E, Bayer EA (1983) Characterization of a cellulose-binding, cellulase containing complex in Clostridium thermocellum. J Bacteriol 156:828–836PubMedGoogle Scholar
  69. 69.
    Lamed R, Setter E, Kenig R, Bayer AE (1983) The cellulosome—a discrete cell surface organelle of Clostridium thermocellum which exhibits separate antigenic, cellulose binding and various cellulolytic activities. Biotechnol Bioeng Symp 13:163–181Google Scholar
  70. 70.
    Lin Y, Tanaka S (2006) Ethanol fermentation from biomass resources: current state and prospects. Appl Microbiol Biotechnol 69:627–642PubMedGoogle Scholar
  71. 71.
    Lynd LR (1996) Overview and evaluation of fuel ethanol from cellulosic biomass: technology, economics, the environment and policy. Annu Rev Energy Environ 21:403–465Google Scholar
  72. 72.
    Lynd LR (1989) Production of ethanol from lignocellulosic material using thermophilic bacteria: critical evaluation of potential and review. Adv Biochem Eng Biotechnol 38:1–52Google Scholar
  73. 73.
    Lynd LR, Cushman JH, Nichols RJ, Wyman CE (1991) Fuel ethanol from cellulosic biomass. Science 251:1318–1323PubMedGoogle Scholar
  74. 74.
    Lynd LR, Weimer PJ, van Zyl WH, Pretorius IS (2002) Microbial cellulose utilization: fundamentals and biotechnology. Microbiol Mol Biol Rev 66:506–577PubMedGoogle Scholar
  75. 75.
    Lynd LR, Jin J, Michels JG, Wyman CE, Dale BE (2003) Bioenergy: background, potential, and policy. A policy briefing prepared for the Center for Strategic and International Studies Washington, DC. (
  76. 76.
    Lynd LR, van Zyl WH, McBride JE, Laser M (2005) Consolidated bioprocessing of cellulosic biomass: an update. Curr Opin Biotechnol 16:577–583PubMedGoogle Scholar
  77. 77.
    Marchetti JM, Miguel VU, Errazu AF (2007) Possible methods for biodiesel production. Renew Sustain Energy Rev 11:1300–1311Google Scholar
  78. 78.
    Mayer F, Coughlan KP, Mori Y, Ljungdahl LG (1987) Macromolecular organization of the cellulolytic complex of Clostridium thermocellum as revealed by electron microscopy. Appl Environ Microbiol 53:2785–2792PubMedGoogle Scholar
  79. 79.
    Meilenz JR (2001) Ethanol production from biomass: technology and commercialization status. Curr Opin Microbiol 4:324–329Google Scholar
  80. 80.
    Mondruzzaman MM, Dien BS, Ferrer B, Hespell RB, Dale BE, Ingram LO, Bothast RJ (1996) Ethanol production from AFEX pretreated corn fiber by recombinant bacteria. Biotechnol Lett 18:985–990Google Scholar
  81. 81.
    Morag E, Bayer EA, Hazlewood GP, Gilbert HJ, Lamed R (1993) Cellulase Ss (Cel S) is synonymous with the major cellobiohydrolase (subunit S8) from the cellulosome of Clostridium thermocellum. Appl Biochem Biotechnol 43:147–151PubMedGoogle Scholar
  82. 82.
    Moriera N (2005) Growing expectations. New technology could turn fuel into a bumper crop. Sci News (Online) 168(14):216–218Google Scholar
  83. 83.
    Newcomb M, Wu JHD (2007) Induction of the Clostridium thermocellum CelC operon by laminaribiose. Proc Natl Acad Sci USA 104:3747–3752PubMedGoogle Scholar
  84. 84.
    Nigam JN (2001) Ethanol production from wheat straw hemicellulose hydrolysate by Pichia stipitis. J Biotechnol 87:17–27PubMedGoogle Scholar
  85. 85.
    Nissen TL, Kielland-Brandt MC, Nielsen J, Villadsen J (2000) Optimization of ethanol production in Saccharomyces cerevisiae by metabolic engineering of the ammonium assimilation. Metab Eng 2:69–77PubMedGoogle Scholar
  86. 86.
    Pasha C, Kuhad RC, Rao CV (2007) Strain improvement of thermotolerant Saccharomyces cerevisiae VS3 strain for better utilization of lignocellulosic substrates. J Appl Microbiol 103:1480–1489PubMedGoogle Scholar
  87. 87.
    Perlack RD, Wright LL, Turhollow AF, Graham RL, Stokes J, Erbach DC (2005) Biomass as feedstock for a bioenergy and bioproducts industry: the technical feasibility of a billion-ton annual supply. Oak Ridge Natl Lab, pp 1–78. (
  88. 88.
    Pessoa A Jr, Roberto IC, Menossi M, Dos Santos RR, Filho SO, Penna TCV (2005) Perspectives on bioenergy and biotechnology in Brazil. Appl Biochem Biotechnol 121–124:59–70Google Scholar
  89. 89.
    Philippidis G, Smith TK, Wyman CE (1993) Study of the enzymatic hydrolysis of cellulose for production of fuel ethanol by simultaneous saccharification and fermentation process. Biotechnol Bioeng 41:846–853PubMedGoogle Scholar
  90. 90.
    Ragauskas AJ, Nagy M, Kim DH, Eckert CA, Hallett JP, Liotta CL (2006) From wood to fuels: integrating biofuels and pulp production. Ind Biotechnol 2:55–65Google Scholar
  91. 91.
    Ratledge C (1979) Resources conservation by novel biological processes I. Grow fats from wastes. Chem Soc Rev 8:283–296Google Scholar
  92. 92.
    Ratledge C (1982) Single cell oil. Enzyme Microb Technol 4:58–60Google Scholar
  93. 93.
    Ratledge C, Wynn JP (2002) The biochemistry and molecular biology of lipid accumulation in oleaginous microorganisms. Adv Appl Microbiol 51:1–51PubMedGoogle Scholar
  94. 94.
    Saha BC, Bothast RJ (1999) Pretreatment and enzymatic saccharification of corn fiber. Appl Biochem Biotechnol 76:65–77PubMedGoogle Scholar
  95. 95.
    Sanderson KW (2007) Are ethanol and other biofuels technologies part of the answer for energy independence? Cereal Food World 52:5–7Google Scholar
  96. 96.
    Schmer MR, Vogel KP, Mitchell RB, Perrin RK (2008) Net energy of cellulosic ethanol from switchgrass. Proc Natl Acad Sci USA 105:464–469PubMedGoogle Scholar
  97. 97.
    Shaw AJ, Podkaminer KK, Desai SG, Bardsley JS, Rogers SR, Thorne PG, Hogsett DA, Lynd LR (2008) Metabolic engineering of a thermophilic bacterium to produce ethanol at high yield. Proc Natl Acad Sci USA 105:13769–13774PubMedGoogle Scholar
  98. 98.
    Shoham Y, Lamed R, Bayer EA (1999) The cellulosome concept as an efficient microbial strategy for the degradation of insoluble polysaccharides. Trends Microbiol 7:275–281PubMedGoogle Scholar
  99. 99.
    Soetoert W, Vandamme E (2006) The impact of industrial biotechnology. Biotechnol J 1:756–769Google Scholar
  100. 100.
    South CR, Hogsett DA, Lynd LR (1993) Continuous fermentation of cellulosic biomass to ethanol. Appl Biochem Biotechnol 39–40:587–600Google Scholar
  101. 101.
    Sticklen M (2006) Plant genetic engineering to improve biomass characteristics for biofuels. Curr Opin Biotechnol 17:315–319PubMedGoogle Scholar
  102. 102.
    Tollefson J (2008) Energy: not your father’s biofuels. Nature 45:880–883Google Scholar
  103. 103.
    Tyurin M, Desai SG, Lynd LR (2004) Electrotransformation studies in Clostridium thermocellum. Appl Environ Microbiol 70:883–890PubMedGoogle Scholar
  104. 104.
    Tyurin MV, Lynd LR, Weigel J (2006) Gene transfer systems for obligately anaerobic thermophilic bacteria. Methods Microbiol 35:309–330Google Scholar
  105. 105.
    Uversky V, Kataeva IA (eds) (2006) Cellulosome. Nova Sci Publ Inc., New YorkGoogle Scholar
  106. 106.
    Wall JD, Harwood CS, Demain A (eds) (2008) Bioenergy. ASM Press, WashingtonGoogle Scholar
  107. 107.
    Wang WK, Wu JHD (1993) Structural features of the Clostridium thermocellum cellulase Ss gene. Appl Biochem Biotechnol 39–40:149–158PubMedGoogle Scholar
  108. 108.
    Wang WK, Kruus K, Wu JHD (1993) Cloning and DNA sequence of the gene coding for Clostridium thermocellum cellulase Ss (CelS), a major cellulosome component. J Bacteriol 175:1293–1302PubMedGoogle Scholar
  109. 109.
    Weil J, Westgate P, Kohlmann K, Ladisch MR (1994) Cellulase pretreatments of lignocellulosic substrates. Enzyme Microb Technol 16:1002–1004PubMedGoogle Scholar
  110. 110.
    Wirth T, Gray CB, Podesta JD (2003) The future of energy policy. Foreign Aff 82:132–155Google Scholar
  111. 111.
    Wu JHD (1993) Clostridium thermocellum cellulosome: new mechanistic concept for cellulose degradation. In: Himmel M, Georgiou G (eds) Biocatalyst design for stability and specificity. American Chemical Society, Washington, DC, pp 251–264Google Scholar
  112. 112.
    Wu JHD, Demain AL (1988) Proteins of the Clostridium thermocellum complex responsible for degradation of crystalline cellulose. In: Aubert JP, Beguin P, Millet J (eds) Biochemistry and genetics of cellulose degradation. Academic Press, New York, pp 117–131Google Scholar
  113. 113.
    Wu JHD, Orme-Johnson WH, Demain AL (1988) Two components of an extracellular protein aggregate of Clostridium thermocellum together degrade crystalline cellulose. Biochemistry 27:1703–1709Google Scholar
  114. 114.
    Wyman CE (1994) Alternative fuels from biomass and their impact on carbon dioxide accumulation. Appl Biochem Biotechnol 45–46:897–915Google Scholar
  115. 115.
    Wyman CE, Hinman ND (1990) Ethanol. Fundamentals of production from renewable feedstocks and use as a transportation fuel. Appl Biochem Biotechnol 24–25:735–753Google Scholar
  116. 116.
    Wyman CE, Dale BD, Elander RT, Hotzapple M, Ladisch MR, Lee YY (2005) Coordinated development of leading biomass pretreatment technologies. Bioresour Technol 96:1959–1966PubMedGoogle Scholar
  117. 117.
    Yamano LP, York SW, Ingram LO (1998) Isolation and characterization of ethanol-tolerant mutants of Escherichia coli KO11 for fuel ethanol production. J Ind Microbiol Biotechnol 20:132–138Google Scholar
  118. 118.
    Yazdani SS, Gonzalez R (2007) Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry. Curr Opin Biotechnol 18:213–219PubMedGoogle Scholar
  119. 119.
    Yomano LP, York SW, Zhou S, Shanmugam KT, Ingram LO (2008) Re-engineering Escherichia coli for ethanol production. Biotechnol Lett 30:2097–2103PubMedGoogle Scholar
  120. 120.
    Zhang Y-HP, Lynd LR (2004) Kinetics and relative importance of phosphorylytic and hydrolytic cleavage of cellodextrins and cellobiose in cell extracts of Clostridium thermocellum. Appl Environ Microbiol 70:1563–1569PubMedGoogle Scholar
  121. 121.
    Zverlov W, Kellermann J, Schwarz WH (2005) Functional subgenomics of Clostridium thermocellum cellulosomal genes: identification of the major catalytic components in the extracellular complex and detection of three new enzymes. Proteomics 5:3646–3653PubMedGoogle Scholar
  122. 122.
    Zverlov VV, Schantz N, Schmitt-Kopplin P, Schwarz WH (2005) Two new major subunits in the cellulosome of Clostridium thermocellum: xyloglucanase Xgh74A and endoxylanase Xyn10D. Microbiology 151:3395–3401PubMedGoogle Scholar

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© Society for Industrial Microbiology 2009

Authors and Affiliations

  1. 1.The Charles A. Dana Research Institute for Scientists Emeriti (R.I.S.E.), HS-330Drew UniversityMadisonUSA

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