Exploring the potential of Burkholderia sacchari to produce polyhydroxyalkanoates

Abstract

Aim: Evaluation of the capability of Burkholderia sacchari to incorporate different monomers into polyhydroxyalkanoates (PHA). Methods and Results: Thirty different carbon sources were evaluated as cosubstrates for B. sacchari growing on glucose with the intention to promote the incorporation of different monomers into the PHA produced by this species. With odd-numbered fatty acids, incorporation of the 3HV monomer was achieved, up to 65 mol% in the case of valerate. With 4-hydroxybutyrate, incorporation of 4HB was obtained, representing 9Á1 mol%. With hexanoic acid, the production of P3HB-co-3HHx was achieved, containing up to 1Á6 mol% of 3HHx. The molar fraction of 3HHx was found to be dependent on the ratio of glucose to hexanoic acid supplied. Metabolic flux analysis revealed a high efficiency of B. sacchari in converting carbon sources into P3HB-co-3HHx. Nevertheless, hexanoic acid was only poorly converted to 3HHx. Conclusions: Burkholderia sacchari is able to incorporate 3HV, 4HB and 3HHx in PHA containing mainly 3HB. The 3HHx content of P3HB-co-3HHx can be controlled by varying the glucose to hexanoic acid ratio. Burkholderia sacchari is highly efficient in converting carbon sources into PHA; however, only 2% of the hexanoic acid supplied could be converted to 3HHx. Significance and Impact of the Study: This is the first report describing an approach to modulate the composition of P3HB-co-3HHx produced by bacteria using mixtures of carbohydrate and hexanoic acid as carbon source.

Growth of Burkholderia sacchari LFM 101 cultivated in glucose, sucrose and glycerol at different temperatures

“…The highest polymer yield was obtained with glucose at 35 °C (41 %), a value greater than the results obtained by Mendonça et al (2013) with the same strain after 24 hours of cultivation (32 % PHA in its cell dry weight), using glucose (10 g L −1…”

“…PHA composition was determined by gas chromatography of propyl esters, as described elsewhere (Mendonça et al, 2013). A volume of 1 mL of organic phase was analyzed after fractionation of the sample (split 1:25) in a gas chromatograph equipped with an HP-5 column (5 % phenyl methyl siloxane, 30 m in length, 0.25mm in diameter, and 0:25 µm in film thickness).…”

“…There are studies in the literature on B. sacchari and PHA production from different substrates, but, for the mostpart, cells were grown at 30 °C (Silva et al, 2000;Mendonça et al, 2013;Lopes et al, 2014). Temperature is an important condition for bioprocesses.…”

“…Potential applications of the PHAs vary due to the diversity of possible monomer combinations (Mendonça et al, 2013;Rodríguez-Contreras et al, 2015). Polyhydroxybutyrate (P3HB) is one of the most studied representatives of the PHA family.…”

Análise de fluxos metabólicos aplicada à biossíntese do polímero biodegradável poli-3-hidroxi-butirato P(3HB) por Burkholderia sacchari.

“…A linhagem escolhida para a realização deste projeto, Burkholderia sacchari, produtora de P(3HB) -um representante dos polihidroxialcanoatos -exibe diferentes vantagens em relação a produção destes plásticos biodegradáveis: demonstrou a capacidade de conversão de carboidratos em P(3HB) de 80% do máximo teórico (GOMEZ et al, 1996), e é apta a consumir sacarose (MENDONÇA et al, 2013) (GOMEZ, 2000).…”