Polyhydroxyalkanoate synthesis from alcohols during the growth of<i>Paracoccus denitrificans</i>

Abstract

Several alcohols were examined as substrates for the polyhydroxyalkanoate synthesis by Paracoccus denitrificans. The bacterium synthesized a homopolyester of poly(3-hydroxybutyrate) from ethanol. When &lt;it&gt;n&lt;/it&gt;-pentanol was used as growth substrate, homopolyester poly(3-hydroxyvalerate) was synthesized, whereas copolyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) accumulated during bacterial growth on &lt;it&gt;n&lt;/it&gt;-propanol. When alcohols were automatically fed as growth substrates, ethanol, &lt;it&gt;n&lt;/it&gt;-propanol, and &lt;it&gt;n&lt;/it&gt;-pentanol gave higher polyester content. Although poly(3-hydroxybutyrate) was synthesized from methanol or &lt;it&gt;n&lt;/it&gt;-butanol, its content was very low. Under nitrogen-deficient conditions, polyester;content in cells increased, especially with ethanol, &lt;it&gt;n&lt;/it&gt;-propanol, and &lt;it&gt;n&lt;/it&gt;-pentanol. Using a mixture of two alcohols &lt;it&gt;P. denitrificans&lt;/it&gt; could synthesize polyesters with varying relative ratios of 3-hydroxybutyrate to 3-hydroxyvalerate.