TECHNOLOGY FOCUS - BIOLOGY - Preparation (Claimed): The preparation of (I) comprises culturing the host cell in a culture medium, under suitable conditions to produce (I) encoded by the expression vector. Preferred Components: (I) further comprises: a domain having an amino acid sequence of at least 70%, preferably 100% identical to amino acids 130-250, 750-842, 580-750, or 24-482 of SEQ ID No. 1; a catalytic domain or cellulose binding domain of a bacterial or archaeal enzyme; and an N-terminal or C-terminal histidine tag. The catalytic domain or cellulose binding domain is encoded by B. fibrisolvens, S. solfataricus, A. cellulolyticus, P. furiosus, P. horikoshii, P. abyssi, A. cellulolyticus, S. lividans, B.fibrisolvens, or T. reesei. (I) comprises identity at glutamates 413 and 506 of SEQ ID No. 1. (I) comprises an amino acid sequence that is at least 70%, preferably 100% identical to SEQ ID No. 5, or SEQ ID No. 16. (I) exhibits cellulase activity at a temperature of greater than 105 degrees C, preferably 95-110 degrees C, in a solution containing up to 50% ionic liquid, 3.2 M potassium chloride, or 4 M sodium chloride. The cellulase activity comprises endoglucanase activity, exoglucanase activity, and beta -glucosidase activity. The cellulase activity has half-life of at least five hours at 100 degrees C, a half-life of at least one hour at 105 degrees C, or a half-life at least 15 minutes at 108 degrees C at a pH of 6.8. The cellulase activity is at least 50 (preferably 70)% maximum over a pH of 4.5-8.75, preferably 8.5. The fermentation product is a biofuel. The biomass is a lignocellulose. Preferred Method: The step of contacting is conducted at a pH of 4.5-8.5, preferably at least 8.5, and at a temperature of 90-110 degrees C, preferably at least 100 degrees C. The step of contacting is conducted in a solution containing potassium chloride, sodium chloride at a concentration of at least 1-4 M, or at least 10%, preferably at least 40% of ionic liquid. The methods further comprises pretreating the biomass prior to the contacting. Preferred Composition: The composition comprises: sodium chloride or potassium chloride at a concentration of at least 1-4 M; and an ionic liquid at a concentration of 20-50% or up to 50%. The composition has a pH of at least 5.5, preferably 8.5. EXAMPLE - E. coli strains comprising BL21 and Rosetta cells, as an N-terminally His tagged protein, derived from plasmid pET16b, in shaking flasks. Each strain was transformed with plasmid and plated on yeast and tryptone (YT) media supplemented with glucose (0.8%) at 35 degrees C. The pET16b N-terminal His-tagged gene appeared to be toxic, producing variable colony size. Only smaller colonies picked from freshly transformed plates resulted in significant expression. These were picked into a small volume of ZYP-0.8G media (5-50 ml) and incubated at 25 degrees C until cells reached an optical density at 550 nm of -0.4. Then 2.5 ml was inoculated per liter of ZYP-5052 rich media for auto-induction. Cells were then incubated with shaking at 20 degrees C or 25 degrees C for 48 hours or 36 hours respectively. Expression was optimized in 1 l shake flask cultures, and subsequently scaled up to 17.5 l in a specialized New Brunswick Bioflow IV fermentor. Cells were grown to an optical density 550 nm of 2.5-3 then harvested by centrifugation at 6000 x g. Expression in the fermentor yielded 3-5 times higher levels of cellulose activity as compared with shake flasks. Cells were lysed by French Pressure Cell in sodium phosphate buffer (50 mM) or N-(2-hydroxyethyl) piperazine-N'-(3-propanesulfonic acid) buffer (50 mM) and incubated for 30 minutes at 90 degrees C to form denatured host proteins.