Cultivation of Trichosporon mycotoxinivorans in sugarcane bagasse hemicellulosic hydrolyzate

Background: The yeast strain IB09 was isolated from the gut of Calosoma sp. (Carabidae, Coleoptera, Insecta) that were collected in the central Amazon rainforest. First, tolerance of the strain to ethanol and heat was tested. Then, IB09 was cultivated in a medium using sugarcane bagasse hemicellulosic hydrolyzate as a carbon source, and cell growth (OD600), specific growth rate (uMAX, h-1), biomass yield (Y B, g.g-1) and relative sugar consumption (RSC, percent) were evaluated. Taxonomic identification was determined by sequencing the ITS1 region of IB09 and comparing it to sequences obtained from the GenBank database (NCBI). Results: IB09 showed both ethanol tolerance and thermotolerance. Relative sugar consumption indicated that IB09 was able to perform saccharification of sugarcane bagasse hemicellulosic hydrolyzate, increasing the total reducing sugar concentration by approximately 50 percent. The μMAX value obtained was 0,20, indicating that cell growth was slow under the assessed conditions. Biomass yield was 0,701 g per g of consumed sugar, which is relatively high when compared with other findings in the literature. After 120 hrs of cultivation, 80,1 percent of total reducing sugar had been consumed. Sequencing of the ITS1 region identified IB09 as Trichosporon mycotoxinivorans. Conclusion: This is the first report to document this species in the central Amazon rainforest at this host. Trichosporon mycotoxinivorans has great biotechnological potential for use in the saccharification of sugarcane bagasse hemicellulosic hydrolyzate and for biomass production with this substrate as carbon source.

Variabilidade genética de Colletotrichum guaranicola usando marcadores AFLP / Variability of Colletotrichum guaranicola using AFLP markers

Foi detectada a variabilidade genética de vinte isolados de Colletotrichum guaranicola (Albuq.) provenientes de diferentes localidades produtoras de guaraná no Amazonas, utilizando-se marcadores moleculares AFLP. Foi possível separar os isolados em dois grupos. O coeficiente de variação genética entre os isolados foi de 0,0216 e a similaridade genética foi de 94,95 por cento, confirmando que os isolados pertencem à mesma espécie, no entanto, foi observada variabilidade intra-específica.

The genetic variability of twenty Colletotrichum guaranicola (Albuq.) isolates from different fields of guarana in Amazonas, was studied using molecular AFLP markers. The isolates were separated into two groups. The genetic variability coefficient was 0.0216 and the genetic similarity was 94.5 percent, confirming that the isolates belongs to the same species, however, an intra-specific variability was observed.