Resumo

PINERO-BONILLA, Judith  e  DIAZ, Isabel. Optimization of a culture medium for Nocardia sp. biomass production with orange residues as a substrate. Rev. Soc. Ven. Microbiol. [online]. 2010, vol.30, n.2, pp.102-108. ISSN 1315-2556.

The yield of Nocardia sp. EP3-MC3 biomass production, from submerged fermentation of orange residues (OR) using the answer surface method (ASM), was evaluated for establishing the optimal conditions of the process. A central orthogonal composed design, with three variables was used: substrate concentration, fermentation time, and temperature, to estimate a second order polynomial model starting from 17 treatments; the exploration region for adjusting the model was 70-150 g/l of OR, 24-60 fermentation hours, and 30-50^oC for incubation of culture media. The OR contain a greater amount of potentially fermentable carbohydrates (65.8%). With ASM we determined the optimal conditions of the fermentation process: pH 6.5, 100 rpm, 30.4^oC, 59.30 h and 71.6/l of OR, under which there was an estimate of 4.5 g/l of biomass, higher than the observed value (2.83 g/l), which suggests the presence of inhibiting factors in the growth medium. The protein content was high (31%), but its digestibility low (59%). It was concluded that microbial biomass production is possible under the conditions used; nevertheless, it should be treated to increase its digestibility

Palavras-chave : Biomass; submerged fermentation; Nocardia; optimization; orange residues.