Evaluation of xylan as carbon source for Weissella spp., a predominant strain in pozol fermentation

Pozol is a traditional Mexican refreshing acid beverage made of hot-alkali treated and fermented maize dough. It has been demonstrated that non-amylolytic lactic acid bacteria as Weissella sp. are important in this process. The aim of this work was to study Weissella spp. strains isolated from pozol from the carbon source perspective. For this purpose, Weissella confusa L9, W. confusa L17, W. confusa Snc40, W. paramesenteroides 3a and W. cibaria 3LA were studied. All the microorganisms were able to metabolize xylose; they also showed β-glucosidase and β-galactosidase activities. The ability to grow in xylan was tested; all the strains showed maximum growth at 24 h but W. confusa L9, W. confusa L17 and W. confusa Snc40 grew from 7.09 to 8.66, 7.08 to 7.84 and 7.26 to 7.94 Log CFU/ml, respectively. W. confusa L9 growth in partially hydrolyzed xylan was evaluated. The evolution of xylooligosaccharides throughout the fermentation was performed. Xylose accumulation was observed (0.28-0.28 mg/ml at 24 h). A preference for xylobiose and xylotriose was observed. β-xylosidase activity was found in W. confusa L9 since consumption of xylooligosaccharides by this microorganism was demonstrated. Hemicellulose is therefore an alternative carbon source sustaining pozol fermentation.