Polyhydroxyalkanoates (PHA) are biocompatible and biodegradable polyesters produced by prokaryotic microbes for energy storage and carbon reserve. These polymers are an option to diminish the massive impact caused by inadequate disposal of synthetic plastics. In this study, evaluation and characterization of PHA produced by Cupriavidus necator (IPT 026 and IPT 027) and Burkholderia cepacia (IPT 119 and IPT 400), using soybean as substrate, were carried out (soybean 15 g L -1 , pH 7.0, 150 rpm, 72 hours). The highest polymer production was achieved using IPT 027 (0.84 ± 0.07 g L -1 ). All PHA produced showed the characteristic bands of polyester functional groups in the FTIR spectra. Polymers synthesized by Cupriavidus necator exhibited initial temperatures of degradation superior to 300oC and higher molecular weights than the ones produced by Burkholderia cepacia, which in turn, exhibited lower crystallinity (inferior to 30%), revealing high influence of the microorganism strain on PHA properties and production.

The aim of this study is to evaluate the bioconversion of residual soybean oil (RSO) into polyhydroxyalkanoates (PHAs) by selecting microorganism and fermentation condition in order to increase PHAs production. PHAs production by Cupriavidus necator IPT 026 using glucose (PHA 1) and RSO (PHA 2) as substrate is 1.15 ± 0.21 and 2.84 ± 0.04 g L−1, respectively. FTIR spectra of PHAs were similar to data reported in literature. PHAs presented low crystallinity (PHA 1: 42.69%; PHA 2: 46.44%), high thermal stability (PHA 1: 271.78 °C; PHA 2: 272.52 °C), and low MW (PHA 1: 140.69 kDa; PHA 2: 254.54 kDa). PHAs produced by RSO are potential candidates for industrial applications, especially ones that demand higher temperatures. This is the first study on the production and characterization of PHAs obtained by C. necator IPT 026 in culture with RSO. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46255.

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O hexametildisiloxano (HMDSO) e o acetato de sec-butila (ACSB) são compostos orgânicos utilizados em diversas aplicações tecnológicas, dentre elas a síntese química de vários produtos de interesse farmacêutico. No presente trabalho, as composições da mistura dos compostos em equilíbrio foram determinadas por meio do método Bolha P, calculado pela equação de estado cúbica com parâmetros de Peng-Robinson para a pressão de 101,3 kPa. Os erros médios percentuais entre os dados calculados e os valores experimentais também foram determinados, o que permitiu mostrar a precisão do modelo estudado em simular o sistema termodinâmico. Dessa maneira, o modelo mostrou-se útil para o cálculo da composição do equilíbrio do sistema binário avaliado, refletindo o comportamento real da mistura com precisão média de 90,57%, sendo, portanto, adequado a aplicações tecnológicas que exijam exatidão relativamente elevada e servindo de base para estudos futuros de modelagem do sistema HMDSO + ACSB. AbstractHexamethyldisiloxane (HMDSO) and sec-butyl acetate (ACSB) are organic compounds used in various technological applications, such as the chemical synthesis of various products of pharmaceutical interest. In the present work, mixture compositions of the compounds in equilibrium were determined by the Bubble P method, calculated by the cubic state equation with Peng-Robinson parameters for the pressure of 101.3 kPa. Mean percentage errors between the calculated and the experimental data were also determined, which allowed to indicate the precision of the model studied for the thermodynamic system modeling. In this way, the model proved to be useful for calculating the equilibrium composition of the evaluated binary system, reflecting the actual behavior of the mixture with an average accuracy of 90.57%; and is therefore suitable for technological applications that require relatively high accuracy and serving as basis for HMDSO + ACSB system future modeling studies.