Diversity of the total bacterial community associated with Ghanaian and Brazilian cocoa bean fermentation samples as revealed by a 16 S rRNA gene clone library

Appl Microbiol Biotechnol. 2010 Aug;87(6):2281-92. doi: 10.1007/s00253-010-2698-9. Epub 2010 Jun 18.

Abstract

Cocoa bean fermentation is a spontaneous process involving a succession of microbial activities, starting with yeasts, followed by lactic acid bacteria and acetic acid bacteria. So far, all microbiological studies about cocoa bean fermentation were based on culture-dependent (isolation, cultivation, and identification), or, more recently, culture-independent (PCR-DGGE, or polymerase chain reaction denaturing gradient gel electrophoresis) methods. Using a metagenomic approach, total DNA was extracted from heap and box fermentations at different time points and from different locations (Ghana and Brazil, respectively) to generate a 16 S rDNA clone library that was sequenced. The sequencing data revealed a low bacterial diversity in the fermentation samples and were in accordance with the results obtained through culture-dependent and a second, culture-independent analysis (PCR-DGGE), suggesting that almost all bacteria involved in the fermentation process are cultivable. One exception was the identification by 16 S rDNA library sequencing of Gluconacetobacter species of acetic acid bacteria that were not detected by the two other approaches. The presence of Enterobacteriaceae related to Erwinia/Pantoea/Tatumella, as revealed by 16 S rDNA library sequencing, suggests an impact of these bacteria on fermentation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / genetics
  • Bacteria / isolation & purification*
  • Bacteria / metabolism*
  • Biodiversity*
  • Brazil
  • Cacao / microbiology*
  • DNA Fingerprinting
  • DNA, Bacterial / genetics
  • Fermentation*
  • Fruit / microbiology
  • Gene Library
  • Ghana
  • RNA, Ribosomal, 16S / genetics

Substances

  • DNA, Bacterial
  • RNA, Ribosomal, 16S