The Composition a evaluate the polymer biodegradable produce for Burkholderia sacchari with the different substrates / Avaliação da composição de polímeros biodegradáveis produzidos por Burkholderia sacchari a partir de diferentes substratos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The bacterial production of polyesters belonging to the polyhydroxyalkanoate family (PHA) has generated biodegradable, biocompatible and environmentally friendly new materials. Properties and applications of PHA depend on monomer composition, which is dependent both on the substrate available and the metabolic apparatus of the PHA-producing microorganism. Burkholderia sacchari is a bacterial species isolated from soil, able to accumulate PHA, whose industrial potential has been tested using sugar cane derivatives. In the present work, the ability of B. sacchari to accumulate PHA was evaluated when thirty different compounds were offered as co-substrates with glucose in nitrogen-free mineral medium. B. sacchari was able to produce PHA from fatty acids containing 2-18 carbon atoms. From fatty acids showing even-numbered carbon chain the homopolymer poly-3-hydroxybutyrate (P3HB) was accumulated. Odd-numbered fatty acids yielded the copolymer poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P3HB-co-3HV), being the 3HV content dependent on the fatty acid supplied. From hexanoic acid there were evidences of 3-hydroxyhexanoate(3HHx) incorporation to the PHA by B. sacchari. Unsaturated fatty acids also led to P3HB synthesis, indicating that fatty acids from plant oils could be used to PHA production by this bacterium. Dicarboxylic acids were excellent substrates for P3HB production by B. sacchari. No evidence of incorporation of carboxyl groups to the PHA side chain was observed. Lactic acid allowed the production of P3HB similarly as observed in other bacteria. Despite no evidence of 4-hydroxybutyrate (4HB) accumulation from -butyrolactone has been obtained NMR analysis of the polymer produced from 4- hydroxybutyrate indicated 4HB incorporation by the PHA synthase of B. saccchari. Gamma-valerolactone and 5-chlorovaleric acid allowed the incorporation of a small fraction of 3HV units to the PHA but NMR analysis was inconclusive to confirm either 4-hydroxyvalerate (4HV) or 5-hydroxyvalerate (5HV) presence. Alcohols were also efficiently used to P3HB accumulation by B. sacchari. However, amylalcohol and 1,4-butanodiol, possible precursors of 3HV and 4HB, respectively, did not show the incorporation of such monomers. Glycerol can be utilized to P3HBproduction by B. sacchari, suggesting that by-products from biodiesel industry could be used in large scale. Results obtained using salicylic and phenylacetic acids demonstrated that the strain B. sacchari does not incorporate aromatic monomers from those sources. In conclusion, results evidenced the versatility of B. sacchari to utilize a wide range of substrates to produce PH;

ASSUNTO(S)

burkholderia sacchari 3hv polímero biodegradável engenharias propionato burkholderia 3-hydroxyvalerate propionate 3-hidroxivalerato plástico biodegradável burkholderia biodegradable plastic 3hv desenvolvimento e otimização de processos industriais.

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