ABSTRACT. Cocoa is naturally fermented in the field before the cocoa seeds are removed for processing. We assessed the dynamics of lactic acid bacteria during cocoa fermentation in Bahia, Brazil. During five days of fermentation, temperature and pH were measured and beans were collected for genomic DNA extraction every 12 h. The DNA was used as a template for amplification with Lac1-Lac2 and Lac3-Lac2 for denaturing gradient gel electrophoresis analyses. pH values ranged from 3.34 to 4.98, while the temperature varied from 23° to 50°C. Lac1-Lac2 primers permitted detection of 11 operational taxonomic units. Twentyeight operational taxonomic units were obtained with the primer pair Lac3-Lac2. It was observed that there were variations between the numbers of operational taxonomic units throughout the process, probably because of changes in pH and temperature. The greatest similarity in Lactic acid bacteria dynamics in cocoa bean fermentation amplified samples was obtained with the primers Lac3-Lac2.
Caves are unique environments filled with complex microbial communities that have adapted to oligotrophy. Communities of fungi and bacteria are commonly studied in touristic caves or are associated with guano or other sources of organic matter, but the archaeal community is often overlooked in these conditions. Based on this gap in the existing literature, the present study aims to evaluate the effect of a unique in vitro contamination event by organic matter in the archaeal community over the course of one year. For that purpose, samples were collected in Gruta Manoel Ioiô, a limestone cave located in Iraquara, Brazil. The collected samples were transported to the laboratory to undergo an enrichment of 0.25% or 0.5% mixture 1:1 (w/w) of yeast and meat extract. Samplings were collected at 0, 1, 6, and 12 months to evaluate the effects on the archaeal community by polymerase chain reaction followed by Denaturing Gel Gradient Electrophoresis (PCR-DGGE). PCR-DGGE profiles show that Operational Taxonomic Units (OTUs) remained in all samples, but variations were observed among the contaminated and control samples, especially at 6 months. Also, an increase in the number of OTUs was observed in samples that received the addition of organic matter in relation to the control. These OTUs were identified as Euryarchaeota and Crenarchaeota. This study showed that the archaeal community could be impacted by organic matter contamination in caves.
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