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Honeys are described possessing different properties including antimicrobial. Many studies have presented this activity of honeys produced by Apis mellifera bees, however studies including activities of stingless bees honeys are scarce. The aim of this study was to compare the antimicrobial activity of honeys collected in the Amazonas State from Melipona compressipes, Melipona seminigra and Apis mellifera against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Chromobacterium violaceum, and Candida albicans. Minimum inhibitory concentrations were determined using the agar dilution method with Müller-Hinton agar (for bacteria) or Saboraud agar (for yeast). Staphylococcus aureus and E. faecalis were inhibited by all honeys at concentrations below 12%, while E. coli and C. violaceum were inhibited by stingless bee honeys at concentrations between 10 and 20%. A. mellifera honey inhibited E. coli at a concentration of 7% and Candida violaceum at 0.7%. C. albicans were inhibited only with honey concentrations between 30 and 40%. All examined honey had antimicrobial activity against the tested pathogens, thus serving as potential antimicrobial agents for several therapeutic approaches. Méis são descritos possuindo diferentes propriedades, incluindo a antimicrobiana. Muitos estudos têm apresentado essa atividade de méis produzidos por abelhas Apis mellifera, no entanto estudos incluindo atividades de méis de abelhas sem ferrão são escassos. O objetivo deste estudo foi comparar a atividade antimicrobiana de méis de Melipona compressipes, Melipona seminigra e A. mellifera, coletados no Estado do Amazonas, contra Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Chromobacterium violaceum, e Candida albicans. As concentrações inibitórias mínimas foram determinadas usando o método de diluição em ágar, com ágar Muller-Hinton (para bactérias) ou ágar Sabouraud (para a levedura). S. aureus e E. faecalis foram inibidos por todos os méis em concentrações inferiores a 12%, enquanto E. coli e C. violaceum foram inibidos por méis de abelhas sem ferrão em altas concentrações entre 10 e 20%. A. mellifera inibiu E. coli na concentração de 7% e C. violaceum em baixa concentração (0,7%). C. albicans foi inibida apenas em concentrações entre 30 e 40% dos méis. Assim, todas as variedades de mel testadas apresentaram atividade antimicrobiana sobre os patógenos testados, servindo assim como agente antimicrobiano potencial para diversas abordagens terapêuticas.

A wild-type yeast that could ferment D-xylose was isolated from the abdominal content of Nasutitermes sp. collected in the Central Amazon rainforest using sugarcane bagasse hemicellulosic hydrolyzate (SBHH) as selective medium. The yeast was identified as Meyerozyma guilliermondii. Its ability to ferment D-xylose was assessed using liquid medium containing Durham tubes. A fermentometer assay showed a low ethanol yield using D-xylose as the carbon source. Cell viability after heat shock and ethanol shock was 39.8% and 56.0%, respectively. Cultivation in SBHH (pH = 5.0) showed its capability to perform saccharification of this substrate, increasing total reducing sugar concentration to 42.6%. The log phase was observed between 36 and 108 hours of cultivation with a highest specific growth rate (µMAX) of 0.10 h-1. After 120 hours, 79.5% of total reducing sugar was consumed giving a biomass yield of 0.52 g/g. The final pH of SBHH (7.6) showed that M. guilliermondii was able to neutralize the acids of this substrate. These results agree with some predictions in the early eighties, which stated that investigations about microbial content of termite guts would provide new tools for bioconversion of lignocellulosic biomass to fuels and other added-value chemicals. This work is the first report for this species associated with termites in the Amazonian habitat.