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Los Polihidroxialcanoatos (PHAs) son biopolímeros de origen microbiano totalmente biodegradables con características físicoquímicas similares a los plásticos sintéticos convencionales, sin embargo, su producción actual es altamente costosa debido principalmente al sustrato o medio de cultivo. En esta investigación se evaluó como sustrato, una mezcla de melaza de caña y vinaza residuales de la industria licorera empleando la cepa referencia Ralstonia eutropha ATCC 17699 para la producción de PHAs. Los resultados obtenidos mostraron potencial en el uso de este medio de cultivo, alcanzando concentraciones de polímero de 3,17 g/L en medio MMS y de 2,71 g/L en el medio M/V con una relación melaza/vinaza de 25/75. El rendimiento de consumo de azucares (sacarosa, fructosa y glucosa) fue del 70,7% y una acumulación del biopolímero del 97,8% respecto a la biomasa producida. La caracterización del biopolímero presento una correlación con la muestra patrón de polihidroxibutirato - PHB del 99,25%.

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In the production of polyhydroxyalkanoates (PHA), the costs of the process are mainly associated with the carbon source and most of the production studies are carried out with commercial strains. In this study, PHA production was evaluated using a strain, SB-34, compared with a referenced strain, Ralstonia eutropha H16, growing in cassava flour hydrolysates as an alternative carbon source. SB-34 reached a biomass maximum of 5,49 ± 0,21 g / L, and PHA product of 3,23 ± 0,21 g / L exceeding the maximum values obtained by R. eutropha H16 (3,8 ± 0,45 g / L and 2,42 ± 0,23 g / L, respectively). Analyzes with FTIR indicate that the polymer obtained with SB-34 is like polyhydroxybutyrate P(3-HB) type. Molecular analysis identified SB-34 as Burkholderia sp. with 96 % of similarity.

BACKGROUND The effect of process integration in bioethanol productivity was experimentally evaluated by coupling an ethanol‐selective pervaporation module to a simultaneous saccharification–fermentation process (SSF). Ethanol concentration in the permeate stream and ethanol productivity were evaluated. Polydimethylsiloxane (PDMS) and silicalite, pure and composite multilayer membranes, supported on porous stainless steel disks, were synthesized and used. Selectivity tests were conducted using ethanol–water mixtures and fermentation broths (5–12 wt% ethanol). RESULTS Multilayer composite membranes showed the best performance among the membranes studied; separation factor, permeance and ethanol concentration in the permeate stream were 31.4, 5.39 kg m−2 h−1 bar−1 (959 gas permeation units (gpu)) and 81.77 wt%, and 26.5, 5.02 kg m−2 h−1 bar−1 (894 gpu) and 77.41 wt%, with model solutions (12.76 wt% ethanol) and actual fermentation broths (11.69 wt% ethanol), respectively. The coupled pervaporator–SSF system, using silicalite‐PDMS multilayer composite membranes, achieved ethanol concentrations in the permeate up to 71.53 wt% and an increase of 3% in productivity with respect to the SSF process without in situ removal of ethanol; permeance and separation factor in the coupled system were 3.25 kg m−2 h−1 bar−1 (578.4 gpu) and 24.8, respectively. CONCLUSIONS The integrated process improves bioreactor productivity and could reduce the energy penalty in the distillation process conventionally used in bioethanol production. © 2016 Society of Chemical Industry