NOVELTY - Recombinant modified Gram-positive bacterium that displays on its surface a minicellulosome comprising two or more cellulolytic enzymes, comprising a protein encoding two or more cohesin domains, where the protein is covalently linked to the surface of the microorganism, each of the cohesin domains is docked to a dockerin attached to a cellulolytic enzyme, the bacterium comprises one or more constructs that encode the dockerin(s) attached to the cellulolytic enzyme(s), and the minicellulosome is self-assembled by the bacterium, is new.    USE - The recombinant modified Gram-positive bacterium including Corynebacterium, Clostridium acetobutylicum, Listeria and Bacillus subtilis is useful for degrading cellulosic biomass into fermentable sugars and for converting a lignocellulosic biomass into bioethanol using a consolidated bioreactor (all claimed), where the fermentable sugars are useful in downstream ethanol producing fermentation reactions performed by Saccharomyces cerevisiae and are D-xylose, L-arabinose, D-galactose, D-glucose, and D-mannose.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) degrading cellulosic biomass into fermentable sugars, comprising contacting the cellulosic biomass with a bacterium under conditions in which the bacteria partially or fully degrade cellulose in the cellulosic biomass to form one or more fermentable sugars;    (2) a consolidated bioreactor for the conversion of a lignocellulosic biomass into bioethanol the bioreactor comprising a culture system that cultures bacteria under conditions, and a culture system that ferments the sugars to form a biofuel; and    (3) identifying cellulolytic enzyme combinations or variants that enhance degradation of a particular substrate, comprising providing the recombinant bacteria, which display at least two cellulolytic enzymes or variants and different bacteria display different enzymes or variants, contacting the substrate with the bacteria, and selecting bacteria that show enhanced degradation of the substrate and/or improved growth on the substrate.