The environmental impact of plastic waste has attracted worldwide attention. Amid the current context of increasing concern for the environment, biodegradable plastics have been widely studied as a replacement for synthetic plastics. Poly(3-hydroxybutyrate) (P(3HB)) is a biopolymer stored as an intracellular energy and reserve source in many microorganisms. Because it is an intracellular product, P(3HB) must be extracted from the cells at the end of the culture. The purpose of this study was to investigate the effect of extraction time, heating temperature, first standing time (after filtration and extraction), second standing time (after P(3HB) precipitation) and solvent amount, during the process of extracting P(3HB) from Cupriavidus necator DSM 545, using propylene carbonate as solvent. The extraction kinetic of P(3HB) with propylene carbonate from thermally treated biomass was evaluated at different temperatures. The physical properties of the P(3HB) obtained were also evaluated. In this case, P(3HB) obtained at optimal conditions of recovery (98%) and purity (99%) was used. Results showed that temperature was the most important factor in these responses for the range of values studied (110-150 ºC).

Lipases are extremely versatile enzymes with large industrial applications and they have been the subject of investigation over the last few years. A great variety of microorganisms can produce this enzyme, such as pluricellular fungi, but their growth need to be optimized due to the variations amongst experiments, which influence the results and reproducibility of the process. The aim of this work was to study the best conditions for inoculum size and age of Geotrichum candidum NRRLY-552, to reduce the variability of the inoculum. The optimized inoculum procedure was determined as: 1 circular area (0.79 cm2) of the solid medium containing cells and spores added to 100 mL of culture medium (5.0 % w/v of peptone, 0.1 % w/v of NaNO3, 0.1 % w/v of MgSO4 and 1.0 % w/v of soybean oil) incubated for 15 h at 30 °C, 250 rpm and with an initial pH of 7.0. This procedure permitted to reduce the experimental error from 30 to 20 % and it has been applied successfully in different studies since then.

Las lipasas son enzimas extremadamente versátiles. Se utilizan en varias aplicaciones industriales, y han sido objeto de atención recientemente. Una diversidad de microrganismos puede producirlas, tales como los hongos pluricelulares. Sin embargo, para el estudio de estas enzimas se debe optimizar su crecimiento, debido a las variaciones entre los experimentos, que influyen en los resultados y en la reproducibilidad de los procesos. El objetivo de este trabajo fue investigar el tamaño y la edad idóneos del inóculo Geotrichum candidum NRRLY-552, con el fin de reducir su variabilidad. El procedimiento optimizado para el inóculo se determinó como una zona circular (0.79 cm2) de medio sólido, que contenía células y esporas, añadido a 100 mL de medio de cultivo (peptona 5.0 % p/v, NaNO3 0.1 % p/v, MgSO4 0.1 % p/v y aceite de soya 1.0 % p/v) que se incubaron durante 15 h a 30 °C, 250 rpm, con un pH inicial de 7.0. Este procedimiento permitió reducir el error experimental de 30 a 20 %, y se ha aplicado con éxito en varios estudios.