Biotechnological production of poly(3-hydroxybutyrate) with Wautersia eutropha by application of green grass juice and silage juice as additional complex substrates

Author: Koller M.   Bona R.   Hermann C.   Horvat P.   Martinz J.   Neto J.   Pereira L.   Varila P.   Braunegg G.  

Publisher: Informa Healthcare

ISSN: 1024-2422

Source: Biocatalysis and Biotransformation, Vol.23, Iss.5, 2005-09, pp. : 329-337

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Abstract

Alternative inexpensive complex nitrogen- and phosphate sources from agriculture, green grass juice (GGJ) and silage juice (SJ), were added to cultivation medium in order to investigate their impact on growth of the well-known polyhydroxyalkanoate (PHA) accumulating strain Wautersia eutropha . The influence of these additives was directly compared with cultivations on defined minimal mineral medium (M) as well as on the same medium supplemented with more expensive complex additives: corn steep liquor (CSL) and casamino acids (CA). It turned out that the supplementation with most complex additives results in shortening of lag-phases of bacterial growth and in higher end-concentrations of residual biomass compared with M-medium. Finally, higher volumetric productivities for poly(3-hydroxybutyrate) (3-PHB) were achieved. The effect of the inexpensive additive SJ on volumetric productivity was similar to the result for the expensive CA (0.653 vs. 0.619gL −1 h −1 ). The same was found for the biomass concentration (7.00 vs. 7.44gL −1 respectively). Together with an economic appraisal presented in this study, the results suggest it is possible to make the sustainable process of microbial PHA-production more economically feasible. A survey of the thermal characteristics and molecular mass properties of the isolated polymers completes this work.

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