First report of collagenase production by Trichosporon sp. strain isolated from pollen of Amazonian bee (Melipona seminigra seminigra).

Trichosporon yeasts are widely employed to produce lipids, lipases, and aspartic peptidases, but there are no previous studies on collagenase production. This work aimed to select the best collagenase producing Amazonian Trichosporon strains. Moreover, a 23-full factorial design (FFD) and a 22-central composite design combined with Response Surface Methodology were applied to optimize production and find the best conditions for hydrolysis of type I bovine collagen. Most of the studied strains had some collagenolytic activity, but the selected one achieved the highest value (44.02 U) and a biomass concentration of 2.31 g/L. The best collagenase production conditions were 160 rpm of agitation, pH 5.5 and a substrate concentration of 4.0 g/L. The former experimental design showed that substrate concentration was the only statistically significant factor on both biomass concentration and collagenase activity, while the latter showed simultaneous effects of substrate concentration and pH on collagenolytic activity, which peaked at pH 5.5-6.4 and substrate concentration of 3.0-3.4 g/L. An additional 2³-FFD was finally used to optimize the conditions collagen hydrolysis, and pH 6, 25 °C and a substrate concentration of 7.5 (g/L) ensured the highest hydrolysis degree. This study is the first that describes optimized conditions of collagenase production by Trichosporon strains.

Draft Genome Sequence of the Wild Edible Mushroom Pleurotus ostreatoroseus DPUA 1720.

The draft whole-genome sequence of the mushroom Pleurotus ostreatoroseus DPUA 1720 (38,588,587 bp) is presented here. This report contributes to the prospective research for bioactive compounds in the genus Pleurotus.

Improving of red colorants production by a new Penicillium purpurogenum strain in submerged culture and the effect of different parameters in their stability.

There is a worldwide interest in the development of processes for colorants production from natural sources such as microorganism. The aim of this study was to optimize red colorants production by Penicillium purpurogenum DPUA 1275 and to evaluate the effect of pH, temperature, salts and polymers on the stability of these colorants. Under optimized conditions, a 78% increase in red colorants production was achieved. The best pH and temperature conditions were obtained at pH 8.0 and 70°C, respectively. In the presence of salts NaCl and Na2 SO4 , both at concentrations of 0.1 and 0.5 M in Mcllvaine buffer (pH 8.0), the red colorants showed good stability. In the presence of both polymers polyethylene glycol and sodium polyacrylate, the red colorants kept their color intensity. Thus, this study presents characteristics of red colorants produced by P. purpurogenum that can be applied in different industries after toxicological examination.

Una técnica para preparaciones permanentes de levaduras / A technique for permanent slides of yeasts

Modificando una técnica indicada por Arta-gaveitía-Allende para microcultivos de levaduras, se obtuvieron entre lamina y laminilla, preparaciones teñidas permanentes que mantienen su integridad por largo tiempo