NOVELTY - Producing lactic acid from biomass material comprises: hydrolyzing the biomass material to form a mixture of monosaccharides; fermenting the monosaccharides in a fermenter with a fermentation broth of a mixed bacteria culture to produce lactic acid and acetic acid; converting at least 90% of the monosaccharides to lactic acid and acetic acid; recovering lactic acid from the fermentation broth at a yield of at least 0.65 g/g of monosaccharides; and recovering acetic acid at a yield of at most 0.065 g/g of monosaccharides.    USE - The method is useful for producing lactic acid from biomass material (claimed), where the lactic acid is used in food and beverages, cosmetics, pharmaceutical, biodegradable plastics and other chemical sectors.    ADVANTAGE - The method: converts at least 90% of the C5 and C6 sugars into lactic acid; provides at least 10 times greater lactic acid than a yield of acetic acid produced; increases a lactic acid production by at least 16% over fermentation with only a single species of either homofermentative bacteria or heterofermentative bacteria; and provides feedstocks into bioproducts with minimal by-products, thus providing for a more profitable and economical production of bioproducts.    DETAILED DESCRIPTION - Producing lactic acid from biomass material comprises: hydrolyzing the biomass material to form a mixture of monosaccharides; fermenting the monosaccharides in a fermenter with a fermentation broth of a mixed bacteria culture to produce lactic acid and acetic acid; converting at least 90% of the monosaccharides to lactic acid and acetic acid; recovering lactic acid from the fermentation broth at a yield of at least 0.65 g/g of monosaccharides; and recovering acetic acid at a yield of at most 0.065 g/g of monosaccharides. The mixed bacteria culture comprises: at least one homofermentative lactic acid bacteria comprising Lactobacillus rhamnosus, Lactobacillus delbrueckii, Lactobacillus casei, Lactobacillus acidophilus or Lactobacillus bulgaricus; and at least one heterofermentative lactic acid bacteria comprising Lactobacillus pentosus, Lactobacillus brevis or Lactobacillus lactis. INDEPENDENT CLAIMS are also included for:    (1) producing lactic acid from non-food biomass material, comprising hydrolyzing non-food biomass material to form a mixture of monosaccharides, fermenting the monosaccharides in a fermenter with a fermentation broth of a mixed bacteria culture to produce lactic acid and co-produced acetic acid, where the mixed bacteria culture comprises at least one homofermentative lactic acid bacteria and at least one heterofermentative bacteria and recovering lactic acid from the fermentation broth;    (2) a system for producing lactic acid from biomass material, comprising a first supply reservoir configured for providing hydrolyzed biomass material, a second supply reservoir configured for providing a mixed bacteria culture medium of at least one homofermentative lactic acid bacteria and at least one heterofermentative lactic acid bacteria, a fermenter configured for receiving the hydrolyzed biomass material and the mixed bacteria culture medium for fermentation of the hydrolyzed biomass material with the mixed bacteria in a resultant fermentation broth, a filter configured for receiving the fermentation broth from the fermenter and separating from the fermentation broth any lactic acid and acetic acid produced by the homofermentative lactic acid bacteria and the heterofermentative lactic acid bacteria, a collector configured for receiving the lactic acid and acetic acid from the filter and at least one pump for feeding hydrolyzed biomass material from the supply reservoir to the fermenter, feeding the mixed bacteria culture to the fermenter, feeding fermentation broth from the fermenter to the filter and/or returning at least a portion of the fermentation broth from the filter back to the fermenter; and    (3) a kit for producing lactic acid from hydrolyzed biomass materials comprising 5-6C sugars, comprising at least one homofermentative lactic acid bacteria and at least one heterofermentative lactic acid bacteria for being combined together in a fermentation broth to convert a substantial portion of the C5 and C6 sugars into lactic acid.