Agro-industrial oily wastes as substrates for PHA production by the new strain Pseudomonas aeruginosa NCIB 40045:: Effect of culture conditions

Production of poly(3-hydroxyalkaonates) (PHA) by Pseudomonas aeruginosa 42A2 from agro-industrial oily wastes was studied. PHA accumulation, throughout the cell cycle, was observed as intracellular accumulation associated to polyphosphate granules. A 54.6% PHA accumulation was obtained-when technical oleic acid (TOA) was used as carbon source. Molecular weight of the polymer was 54.7 Da. The polymer was amorphous, with glass transition at -47.5 degrees C and thermal degradation at 293 degrees C. PHA production and monomer composition were affected by K-La and temperature. The most relevant characteristic of the polymer produced at low aeration rates (K-La, 0.06 s(-1)) were the unusual C-14:2 (13%) and the increase Of C-12:1 (42.2%). The highest amount of unsaturated monomers was found in the polymer produced at 18 degrees C (64.4%). PHA accumulation ranged between 66.1% when waste-free fatty acids from soybean oil (WFFA) were used as carbon substrate, 29.4% when waste frying oil (WFO) was used and 16.8% when glucose was used. Depending on the substrate supplied a wide range of components was observed. Major saturated or unsaturated components of the polymer found were C-10:0, C-12:0 and C-8:0 or C-12:1 and C-14:1, respectively. When glucose was used as carbon substrate C-9:0, C-11:0 and C-16:0 were found. (c) 2005 Elsevier B.V. All rights reserved.