TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method further comprises producing lactic acid at a productivity rate of 0.5-1 g/l-hour. The fermenting comprises fermenting the monosaccharides in a single stage with both the homofermentative bacteria and the heterofermentative bacteria. The fermenting comprises: fermenting the monosaccharides in a first fermentation broth with only the homofermentative bacteria to convert a first portion of the monosaccharides into lactic acid; adding the heterofermentative bacteria to the first fermentation broth to form a second fermentation broth; and fermenting additional monosaccharides in the second fermentation broth with both the homofermentative bacteria and the heterofermentative bacteria to convert an additional portion of the monosaccharides into lactic acid. The biomass material comprises cellulose and hemicelluloses, where the hydrolyzing comprises: contacting the biomass material and at least one cellulase to convert the cellulose into glucose; and contacting the biomass material and at least one xylanase to convert the hemicellulose into xylose, glucose and at least one additional pentose. The xylanase converts the hemicellulose into glucose, xylose, and at least one of glucuronic acid, mannose, galactose, rhamnose, and arabinose. The biomass comprises cellulose, hemi-cellulose and lignins, where the method further comprises pre-treating the biomass material prior to the hydrolyzing to break down and remove the lignins from the biomass material. The pre-treating comprises contacting the biomass material and an acid at 60-170 degrees C, preferably 80-150 degrees C for 2-80 minutes where the acid is 0.5-1.5 M of at least one of sulfuric acid, hydrochloric acid or nitric acid. The pre-treating comprises contacting the biomass material and a base at 25-80 degrees C, preferably 25-60 degrees C for 0.5-5 hours, where the base is 0.1-2 M of at least one of sodium hydroxide, potassium hydroxide or calcium hydroxide The fermenter comprises a continuous feed fermenter with continuous recovery of lactic acid, where the method further comprises: introducing a flow of the monosaccharides into the fermentation broth in the fermenter; fermenting the monosaccharides in the fermenter; and continuously recovering lactic acid from the fermenter at a production rate of 2.5-3.1 g/l-hour. After fermenting, the fermentation broth comprises the homofermentative lactic acid bacteria, the heterofermentative lactic acid bacteria, undigested monosaccharides, and a liquid broth portion comprising the lactic acid, where the recovering comprises: passing the fermentation broth through a filter having a pore size for retaining the undigested monosaccharides, the homofermentative lactic acid bacteria and the heterofermentative lactic acid bacteria in the fermentation broth while allowing the liquid broth portion to pass through; collecting the liquid broth portion; and purifying the lactic acid from the liquid broth portion. The purifying comprises: adding calcium carbonate to the liquid broth portion to form calcium lactate; filtering calcium lactate from the liquid broth portion; reacting the calcium lactate with sulfuric acid to form lactic acid and calcium sulfate; and filtering the calcium sulfate out of the lactic acid. During fermenting, the fermentation broth comprises the homofermentative lactic acid bacteria, the heterofermentative lactic acid bacteria, monosaccharides, and the lactic acid, where the recovering comprises in-situ recovering and concentrating of the lactic acid by a filtration system. The method further comprises: introducing, at least periodically, a flow of the monosaccharides into the fermentation broth in the fermenter; pumping the fermentation broth through a filter module comprising a membrane having a pore size for retaining the monosaccharides, the homofermentative lactic acid bacteria and the heterofermentative lactic acid bacteria in a first fermentation broth portion while allowing the lactic acid to pass through in a second fermentation broth portion; separating the second fermentation broth portion from the first fermentation broth portion in the filter module; returning the first fermentation broth portion to the fermenter; collecting the second fermentation broth portion in a collection vessel; and purifying the lactic acid from the second fermentation broth portion. The method further comprises: introducing, at least periodically, a flow of the monosaccharides into the fermentation broth in the fermenter; pumping the fermentation broth through the filtration system; separating the second fermentation broth portion from the first fermentation broth portion in a first filter module comprising a membrane having a pore size for retaining the at least one homofermentative lactic acid bacteria and the at least one heterofermentative lactic bacteria in a first fermentation broth portion while allowing the monosaccharides, and the lactic acid to pass through in a second fermentation broth portion; separating the fourth fermentation broth portion from the third fermentation broth portion in a second filter module comprising a membrane having a pore size for retaining the monosaccharides in the third fermentation broth portion while allowing the lactic acid to pass through in a fourth fermentation broth portion; returning the first and third fermentation broth portions to the fermenter; collecting the fourth fermentation broth portion in a collection vessel; and purifying the lactic acid from the second fermentation broth portion. The method further comprises prior to the fermenting, activating the homofermentative bacteria and the heterofermentative bacteria in Man Rogosa Sharpe media. The method of producing lactic acid from non-food biomass material further comprises: converting at least 90% of the monosaccharides into lactic acid; and producing lactic acid at a yield of at least 10 times greater than a yield of acetic acid produced. The method of producing lactic acid from non-food biomass material further comprises producing lactic acid at a yield which is at least 16% greater than a yield of lactic acid produced by fermentation with only a single species of either homofermentative bacteria or heterofermentative bacteria. Preferred Components: The homofermentative lactic acid bacteria comprises Lactobacillus rhamnosus, and the heterofermentative lactic acid bacteria comprises Lactobacillus pentosus. The cellulase comprises endocellulase, exocellulase and cellobiase. The xylanase comprises endo-1,4- beta -xylanase, exo-1,3- beta -xylosidase, and exo-1,4- beta -xylosidase. The monosaccharides comprise glucose, xylose and at least one of mannose, galactose, rhamnose, and arabinose. The biomass comprises non-food biomass. The biomass comprises at least one of forest residues, municipal solid waste, waste paper and crop residues, preferably at least one of sawdust, corn stover, wheat straw, rice straw, switch grass, bagasse, poplar wood, paper mill waste and municipal paper waste. The system comprises or is a continuous flow, non-batch system configured for continuous output of lactic acid from fermenting biomass material. Lactic acid yield is increased by at least 18% over production with only a single species of either homofermentative bacteria or heterofermentative bacteria. Substantially all of the hydrolyzed biomass material is converted to lactic acid and acetic acid, and the amount of lactic acid produced is at least 10 times greater than the amount of acetic acid produced. The fermentation broth comprises the hydrolyzed biomass material, bacteria, and a liquid component comprising the lactic acid and acetic acid. The filter comprises a flow through filter module comprising at least one filter membrane having a pore size for retaining the hydrolyzed biomass material and the bacteria in the portion of the fermentation broth returned to the fermenter while allowing at least a portion of the liquid component to pass through to the collector. The filter module comprises: a first membrane for receiving fermentation broth from the fermenter and having a pore size for retaining the bacteria in a first fermentation broth portion while allowing the hydrolyzed biomass material and a first portion of the liquid component to pass through; a second membrane for receiving the first portion of the liquid component and having a pore size for retaining the hydrolyzed biomass material in a second fermentation broth portion while allowing at least an additional portion of the liquid component to pass through to the collector; and a return for returning the first fermentation broth portion and the second fermentation broth portion to the fermenter. The first membrane has a molecular weight cutoff of 1500 Da. The second membrane has a molecular weight cutoff of 500 Da. The pump comprises: at least a first pump for feeding hydrolyzed biomass material from the first supply reservoir to the fermenter; at least one second pump for feeding the mixed bacteria culture medium from the second supply reservoir to the fermenter; and at least one third pump for feeding the fermentation broth from the fermenter to the filter and returning the fermentation broth from the filter back to the fermenter. The third pump has a flow rate of at least 150 ml/minute. The system further comprises: a hydrolysis vessel for receiving biomass material and at least one cellulase for hydrolysis of biomass material into glucose, xylose and at least one additional pentose; and a pre-treatment vessel for pre-treating biomass material prior to the hydrolysis to break down and remove lignins from the biomass material. EXAMPLE - No suitable example given.