TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The enzyme functions in a step of the pathway to convert pyruvate to acrylate. The engineered metabolic pathway involves: (a) conversion of pyruvate to lactate; and (b) direct conversion of lactate to acrylate; or (a1) conversion of pyruvate to lactate; (b1) conversion of lactate to lactoyl-CoA; (c1) conversion of lactoyol-CoA to acryloyl-CoA; and (d1) conversion of acryloyl-Co A to acrylate; or (a2) conversion of pyruvate to L- alpha -alanine; (b2) conversion of L- alpha -alanine to L-asparate; (c2) conversion of L-asparate to beta -alanine; (d2) conversion of beta -alanine to beta -alanyl-CoA; (e2) conversion of beta -alanyl-CoA to acryloyl-CoA; and (f2) conversion of acryloyl-Co A to acrylate. The conversion of lignocellulosic biomass to acrylate results in the generation of net positive amount of adenosine triphosphate (ATP). Preferred Enzyme: The enzymes is an enzyme of Clostridium propionicum that converts pyruvate to lactate or converts lactate to acrylate. The enzymes comprises an amino acid sequence having at least 85 (preferably at least 97)% identity with the amino acid sequence of an enzyme of Clostridium propionicum that converts pyruvate to lactate or converts lactate to acrylate. The enzyme is an enzyme of Clostridium propionicum that converts lactoyl-CoA to acryloyl-CoA or converts acryloyl-CoA to acrylate. The enzymes comprises an amino acid sequence having at least 85 (preferably 97)% identity with the amino acid sequence of an enzyme of Clostridium propionicum that converts lactoyl-CoA to acryloyl-CoA or converts acryloyl-CoA to acrylate. The enzymes is an enzyme of Clostridium propionicum that converts pyruvate to L- alpha -alanine, converts L- alpha -alanine to L-aspartate, converts L-aspartate to beta -alanine, converts beta -alanyl-CoA to acryloyl-CoA, or converts acryloyl-CoA to acrylate. The enzymes comprises an amino acid sequence having at least 85 (preferably 97)% identity with the amino acid sequence of an enzyme of Clostridium propionicum that converts pyruvate to L- alpha -alanine, converts L- alpha -alanine to L-aspartate, converts L-aspartate to beta - alanine, converts beta -alanyl-CoA to acryloyl-CoA, or converts acryloyl-CoA to acrylate. The enzyme of Clostridium propionicum that converts pyruvate to lactate or converts lactate to acrylate is selected from D-lactate dehydrogenase and hypothetical lactate dehydratase. The enzyme of Clostridium propionicum that converts lactoyl-CoA to acryloyl-CoA or converts acryloyl-CoA to acrylate is selected from D-lactoyl-CoA dehydratase and hypothetical lactate (acrylate) CoA transferase. The enzyme of Clostridium propionicum that converts pyruvate to L- alpha -alanine, converts L- alpha -alanine to L-aspartate, converts L-aspartate to beta -alanine, converts beta -alanyl-CoA to acryloyl-CoA, or converts acryloyl-CoA to acrylate is selected from alanine aminotransferase, glutamate dehydrogenase, aspartate 4-decarboxylase, beta -alanyl-CoA:ammonia lyase and hypothetical beta -alanine (acrylate) CoA transferase. Preferred Biomass: The lignocellulosic biomass is selected from grass, switch grass, cord grass, rye grass, reed canary grass, mixed prairie grass, miscanthus, sugar-processing residues, sugarcane bagasse, sugarcane straw, agricultural wastes, rice straw, rice hulls, barley straw, corn cobs, cereal straw, wheat straw, canola straw, oat straw, oat hulls, corn fiber, stover, soybean stover, corn stover, forestry wastes, recycled wood pulp fiber, paper sludge, sawdust, hardwood and/or softwood. The lignocellulosic biomass is selected from corn stover, sugarcane bagasse, switchgrass, and poplar wood. The lignocellulosic biomass is poplar wood, paper sludge. The host cell is a thermophilic or mesophilic bacterial cell. Preferred Microorganism: The microorganism is a Gram-negative bacterium or a Gram-positive bacterium. The microorganism is a species of the genera Thermoanaerobacterium, Thermoanaerobacter, Clostridium, Geobacillus, Saccharococcus, Paenibacillus, Bacillus, Caldicellulosiruptor, Anaerocellum, or Anoxybacillus. The microorganism is a bacterium selected from: Thermoanaerobacterium thermosulfurigenes, Thermoanaerobacterium aotearoense, Thermoanaerobacterium polysaccharolyticum, Thermoanaerobacterium zeae, Thermoanaerobacterium xylanolyticum, Thermoanaerobacterium saccharolyticum, Thermoanaerobium brockii, Thermoanaerobacterium thermosaccharolyticum, Thermoanaerobacter thermohydrosulfuricus, Thermoanaerobacter ethanolicus, Thermoanaerobacter brocki, Clostridium thermocellum, Clostridium cellulolyticum, Clostridium phytofermentans, Clostridium straminosolvens, Geobacillus thermoglucosidasius, Geobacillus stearothermophilus, Saccharococcus caldoxylosilyticus, Saccharoccus thermophilus, Paenibacillus campinasensis, Bacillus flavothermus, Anoxybacillus kamchatkensis, Anoxybacillus gonensis, Caldicellulosiruptor acetigenus, Caldicellulosiruptor saccharolyticus, Caldicellulosiruptor kristjanssonii, Caldicellulosiruptor owensensis, Caldicellulosiruptor lactoaceticus, and Anaerocellum thermophilum (preferably Clostridium thermocellum, and Thermoanaerobacterium saccharolyticum).    TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Components: In the recombinant thermophilic or mesophilic microorganism, a first native gene is partially, substantially, or completely deleted, silenced, inactivated, or down-regulated, which first native gene encodes a first native enzyme involved in the metabolic production of an organic acid or its salt, thereby increasing the native ability of the thermophilic or mesophilic microorganism to produce lactate as a fermentation product. The first native enzyme is selected from lactate dehydrogenase, acetate kinase, phosphotransacetylase, pyruvate formate lyase, alcohol dehydrogenase, and aldehyde dehydrogenase. The nucleotide sequence encodes an enzyme of Clostridium propionicum that converts pyruvate to lactate or converts lactate to acrylate. The nucleotide sequence encodes an enzyme comprising an amino acid sequence having at least 90 (preferably at least 95)% identity with the amino acid sequence of an enzyme of Clostridium propionicum that converts pyruvate to lactate or converts lactate to acrylate. The nucleotide sequence encodes an enzyme of Clostridium propionicum that converts lactoyl-CoA to acryloyl-CoA or converts acryloyl-CoA to acrylate. The nucleotide sequence encodes an enzyme having at least 90 (preferably at least 95)% identity with an enzyme of Clostridium propionicum that converts lactoyl-CoA to acryloyl-CoA or converts acryloyl-CoA to acrylate. The nucleotide sequence encodes an enzyme of Clostridium propionicum that converts pyruvate to L- alpha -alanine, converts L- alpha -alanine to L-aspartate, converts L-aspartate to beta -alanine, converts beta -alanyl-CoA to acryloyl-CoA, or converts acryloyl-CoA to acrylate. The nucleotide sequence encodes an enzyme comprising an amino acid sequence having at least 90 (preferably at least 95)% identity with the amino acid sequence of an enzyme of Clostridium propionicum that converts pyruvate to L- alpha -alanine, converts L- alpha -alanine to L-aspartate, converts L-aspartate to beta -alanine, converts beta -alanyl-CoA to acryloyl-CoA, or converts acryloyl-CoA to acrylate. EXAMPLE - No suitable example is given.