Department of Biology, Federal University of Lavras (UFLA), CP 3037 - Campus Universitário, CEP 37.200-000 Lavras, MG, Brazil.
Int J Food Microbiol. 2012 May 15;156(2):112-21. doi: 10.1016/j.ijfoodmicro.2012.03.010. Epub 2012 Mar 20.
Caxiri is a traditional fermented alcoholic beverage produced from cassava and sweet potatoes by the indigenous Juruna or Yudjá people in Brazil. Our results showed that caxiri fermentation is invariably associated with the following: (i) an increase in the total microbial population, with yeast being the largest group detected; (ii) a decrease in reducing sugars, malic, tartaric, succinic, oxalic and propionic acid; and (iii) a final product characterised by a high content of ethanol and a high concentration of lactic acid. The microbial community dynamics were investigated by culture-based and culture-independent approaches. Fermentation was assisted by a complex microbial community that changed in structure and composition during the fermentative process. The bacterial population ranged from 3.05 to 5.33 log/mL, and the yeast population varied from 3.27 log CFU/mL to 7.34 log CFU/mL, showing that yeasts dominated the fermentation process after 48 h. A total of 343 colonies of bacteria and 205 colonies of yeasts were isolated and initially grouped by Amplified Ribosomal DNA Restriction Analysis (ARDRA) and by biochemical features. Phylogenetic analysis of the 16S rRNA gene sequences of representative isolates showed that the bacteria were mainly represented by endospore-forming low-G+C content Gram-positive bacilli (Bacillus spp.; 61.5% of the isolates), with Bacillus pumilus, Bacillus spp. (Bacillus cereus group), and Bacillus subtilis being the main species identified. The species Sphingomonas sp. and Pediococcus acidilactici were also found. The dominant yeast identified was Saccharomyces cerevisiae. Rhodotorula mucilaginosa, Pichia membranifaciens, Pichia guilliermondii and Cryptococcus luteolus were also found. According to the Polymerase Chain Reaction and Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analysis, the microbial communities present during fermentation were probably from the raw materials, ambient or present on the utensils used during beverage preparation. The results indicated the necessity to combine both culture-dependent and culture-independent methods for a better description of the microbial communities in indigenous starch fermentations. Also, pH values decreased from 4.76 to 3.15 during fermentation. The ethanol concentration was 83.9 g/L and lactic acid reached 27.89 g/L by the end of the fermentation process.
卡希里酒是巴西原住民茹鲁纳人或尤达贾人用木薯和红薯酿造的一种传统发酵酒精饮料。我们的结果表明，卡希里酒发酵总是伴随着以下变化：（i）总微生物群增加，酵母是检测到的最大群体；（ii）还原糖、苹果酸、酒石酸、琥珀酸、草酸和丙酸减少；（iii）最终产品的特点是乙醇含量高，乳酸浓度高。通过基于培养和非培养的方法研究了微生物群落的动态变化。发酵过程中，微生物群落结构和组成发生变化，发酵过程中微生物群落协助发酵。细菌数量从 3.05 到 5.33 log/mL，酵母数量从 3.27 log CFU/mL 到 7.34 log CFU/mL，表明酵母在 48 小时后主导发酵过程。共分离出 343 株细菌和 205 株酵母，并用扩增核糖体 DNA 限制性分析（ARDRA）和生化特征初步分组。代表性分离株 16S rRNA 基因序列的系统发育分析表明，细菌主要由形成内孢子的低 G+C 含量革兰氏阳性杆菌（芽孢杆菌属；61.5%的分离株）组成，其中发现了短小芽孢杆菌、芽孢杆菌属（蜡样芽孢杆菌群）和枯草芽孢杆菌。还发现了鞘氨醇单胞菌属和戊糖片球菌属。鉴定出的优势酵母是酿酒酵母。还发现了黏性红酵母、膜醭毕赤酵母、毕赤酵母和黄孢原毛平革菌。根据聚合酶链反应和变性梯度凝胶电泳（PCR-DGGE）分析，发酵过程中存在的微生物群落可能来自原料、环境或饮料制备过程中使用的器具。结果表明，有必要结合依赖培养和非依赖培养的方法，以更好地描述土著淀粉发酵中的微生物群落。此外，发酵过程中 pH 值从 4.76 下降到 3.15。发酵结束时，乙醇浓度达到 83.9 g/L，乳酸达到 27.89 g/L。
