ABSTRACT The aim of the present research was characterize the enzymatic activity of ß-galactosidase isolated from a liquid culture of Pleurotus ostreatus based on whey. For this, samples of mycelium of P. ostreatus were cultivated in agar whey and incubated for 20-24 days. Fragments of 1 cm2 of the mycelial growth were transferred to culture media containing whey broth, leaving in growth for 21 days. The liquid cultures were filtered to obtain the crude extract, from which the enzymatic activity, the concentration of enzyme, the effect of pH, temperature, enzyme, substrate ortho-nitrophenyl-β-galactopyranoside (ONPG) and the incubation time were determined; being found that, the crude extract of ß-galactosidase presents an enzymatic activity of 0.394 U/mL, a protein concentration of 0.8545 mg/mL and a specific activity of 0.461 U/mg. The optimal pH and temperature values of the enzyme...

En esta investigación se determinó el efecto del Caldo Nutritivo (CN), Caldo Nutritivo Enriquecido (CNE), Caldo Melaza (CM) y Caldo Harina de Soya (CHS) sobre el crecimiento, esporulación y producción de cristales de Bacillus thuringiensis 1K, 2K, 14B y 4A. Los pre-inóculos se prepararon en Plate Count Agar y los inóculos en CN, CNE, CM y CHS. Cada inóculo (40 mL) se adicionó a biorreactores estériles conteniendo 360 mL de CN, CNE, CM y CHS, y se incubaron durante 72 horas a 30°C y en agitación constante (130 rpm). El crecimiento se midió mediante recuentos de viables en placa (UFC/mL), y el número de esporas y de cristales mediante coloración con cristal violeta. B. thuringiensis 1K y B. thuringiensis 4A presentan la mayor velocidad específica de crecimiento en CN (μ=0.35 y μ=0.26 h-1 respectivamente), B. thuringiensis 2K en CNE (μ=0.29 h-1) y B. thuringiensis 14B en C...