title: Diversity of lactic acid bacteria of the bioethanol process.
abstract: BACKGROUND
  Bacteria may compete with yeast for nutrients during bioethanol production process, potentially causing economic losses. This is the first study aiming at the quantification and identification of Lactic Acid Bacteria (LAB) present in the bioethanol industrial processes in different distilleries of Brazil.
  
  
  RESULTS
  A total of 489 LAB isolates were obtained from four distilleries in 2007 and 2008. The abundance of LAB in the fermentation tanks varied between 6.0 × 105 and 8.9 × 108 CFUs/mL. Crude sugar cane juice contained 7.4 × 107 to 6.0 × 108 LAB CFUs. Most of the LAB isolates belonged to the genus Lactobacillus according to rRNA operon enzyme restriction profiles. A variety of Lactobacillus species occurred throughout the bioethanol process, but the most frequently found species towards the end of the harvest season were L. fermentum and L. vini. The different rep-PCR patterns indicate the co-occurrence of distinct populations of the species L. fermentum and L. vini, suggesting a great intraspecific diversity. Representative isolates of both species had the ability to grow in medium containing up to 10% ethanol, suggesting selection of ethanol tolerant bacteria throughout the process.
  
  
  CONCLUSIONS
  This study served as a first survey of the LAB diversity in the bioethanol process in Brazil. The abundance and diversity of LAB suggest that they have a significant impact in the bioethanol process.
authors.affiliation: Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Brigida T L
authors.initials: BT
authors.lastname: Lucena
authors.forename: Billy M
authors.initials: BM
authors.lastname: dos Santos
authors.forename: João Ls
authors.initials: JL
authors.lastname: Moreira
authors.forename: Ana Paula B
authors.initials: AP
authors.lastname: Moreira
authors.forename: Alvaro C
authors.initials: AC
authors.lastname: Nunes
authors.forename: Vasco
authors.initials: V
authors.lastname: Azevedo
authors.forename: Anderson
authors.initials: A
authors.lastname: Miyoshi
authors.forename: Fabiano L
authors.initials: FL
authors.lastname: Thompson
authors.forename: Marcos Antonio
authors.initials: MA
authors.lastname: de Morais
mesh_terms: D044822:Biodiversity; D056804:Biofuels / Q000032:analysis; D001938:Brazil; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D007218:Industrial Microbiology; D019344:Lactic Acid / Q000378:metabolism; D007778:Lactobacillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D056804:Biofuels; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid; D000431:Ethanol