Resumen

GRADOS TORREZ, Ricardo; ALVAREZ ALIAGA, María Teresa; GIMENEZ TURBA, Alberto  y  MATTIASSON, Bo. Anaerobic digestion of agricultural waste by microbial consortia for the polyhydroxyalkanoates production. BIOFARBO [online]. 2008, vol.16, n.1, pp. 28-35. ISSN 1813-5363.

Polyhydroxyalkanoates (PHAs) have been used as an alternative response to the environmental problems caused by polyethylene accumulation. Thus, the present work has been performed in two stages: (1) the volatile fatty acids (VFAs) production by TACANA, ISA and OSCAR consortia from agricultural waste, such as: barley (Hordeum vulgare), quinoa (Chenopodium quinoa), soybean (Glycine max), oats(Avena sativa), wheat (Triticum sativum), alfa (Medicago sativa) and rice husk (Oryza sativa), from these, the highest concentration of VFAs (6.85g/L)  was obtained from anaerobic digestion of barley straw with TACANA consortia. The optimization of the conditions gave an increase of VFAs production in more than a 60% (10.62g/L). What´s more, the enzyme activity from batch cultivation showed a clear increase in the exocellulolitic activity (6.85g/L), which is related to the high VFAs production. (2) In the second stage, the consortia were subjected to 4, 8 and 12 hrs of feast/famine periods with VFAs as carbon source. This evaluation was performed trough a Sudan Black staining test, showing that TACANA consortia had the highest number of microorganisms able to accumulate PHAs. It is in this way that it was proved that the PHAs production from mixed cultures is a good alternative to be used in industrial scale, instead of using pure strains

Palabras llave : Polyhydroxyalkanoates; anaerobic digestion; volatile fatty acids.