Fermentative lactic acid production is currently impeded by low pH tolerance of the production organisms, the successive substrate consumption of the strains and/or the requirement to apply purified substrate streams. We identifiedLactobacillus brevisIGB 1.29 in compost, which is capable of producing lactic acid at low pH values from lignocellulose hydrolysates, simultaneously consuming glucose and xylose. In this study, we comparedLactobacillus brevisIGB 1.29 with the reference strainsLactobacillus brevisATCC 367,Lactobacillus plantarumNCIMB 8826 andLactococcus lactisJCM 7638 with regard to the consumption of C5- and C6-sugars. Simultaneous conversion of C5- and C6-monosaccharides was confirmed forL. brevisIGB 1.29 with consumption rates of 1.6 g/(L h) for glucose and 1.0 g/(L h) for xylose. Consumption rates were lower forL. brevisATCC 367 with 0.6 g/(L h) for glucose and 0.2 g/(L h) for xylose. Further trials were carried out to determine the sensitivity towards common toxic degradation products in lignocellulose hydrolysates: acetate, hydroxymethylfurfural, furfural, formate, levulinic acid and phenolic compounds from hemicellulose fraction.L. lactiswas the least tolerant strain towards the inhibitors, whereasL. brevisIGB 1.29 showed the highest tolerance.L. brevisIGB 1.29 exhibited only 10% growth reduction at concentrations of 26.0 g/L acetate, 1.2 g/L furfural, 5.0 g/L formate, 6.6 g/L hydroxymethylfurfural, 9.2 g/L levulinic acid or 2.2 g/L phenolic compounds. This study describes a new strainL. brevisIGB 1.29, that enables efficient lactic acid production with a lignocellulose-derived C5- and C6-sugar fraction.