masterThesis
Produção de enzimas por fungos em fermentação semi-sólida utilizando bagaço de coco e pedúnculo de caju como substratos
Fecha
2014-01-16Registro en:
OLIVEIRA JÚNIOR, Sérgio Dantas de. Produção de enzimas por fungos em fermentação semi-sólida utilizando bagaço de coco e pedúnculo de caju como substratos. 2014. 121 f. Dissertação (Mestrado em Pesquisa e Desenvolvimento de Tecnologias Regionais) - Universidade Federal do Rio Grande do Norte, Natal, 2014.
Autor
Oliveira Júnior, Sérgio Dantas de
Resumen
The production of enzymes by microorganisms using organic residues is important and it can
be associated with several applications such as food and chemical industries and so on. The
objective of this work is the production of CMCase, Xylanase, Avicelase and FPase enzymes
by solid state fermentation (SSF) using as substrates: bagasse of coconut and dried cashew
stem. The microorganisms employed are Penicillium chrysogenum and an isolated fungus
from the coconut bark (Aspergillus fumigatus). Through the factorial design methodology and
response surface analysis it was possible to study the influence of the humidity and pH. For
Penicillium chrysogenum and the isolated fungus, the coconut bagasse was used as culture
medium. In another fermentation, it was used the mixture of coconut bagasse and cashew
stem. Fermentations were conducted using only the coconut bagasse as substrate in cultures
with Penicillium chrysogenum fungus and the isolated one. A mixture with 50% of coconut
and 50% of cashew stem was employed only for Penicillium chrysogenum fungus, the
cultivation conditions were: 120 hours at 30 °C in BOD, changing humidity and pH values. In
order to check the influence of the variables: humidity and pH, a 2
2
factorial experimental
design was developed, and then two factors with two levels for each factor and three
repetitions at the central point. The levels of the independent variables used in ascending
order (-1, 0, +1), to humidity, 66%, 70.5% and 75% and pH 3, 5 and 7, respectively. The
software STATISTICA
TM
(version 7.0, StatSoft, Inc.) was used to calculate the main effects
of the variables and their interactions. The response surface methodology was used to
optimize the conditions of the SSF. A chemical and a physic-chemical characterization of the
coconut bagasse have determined the composition of cellulose (%) = 39.09; Hemicellulose
(%) = 23.80, Total Lignin (%) = 36.22 and Pectin (%) = 1.64. To the characterization of
cashew stem, the values were cellulose (g) = 15.91 Hemicellulose (%) = 16.77, Total Lignin
(%) = 30.04 and Pectin (%) = 15.24. The results indicate the potential of the materials as
substrate for semisolid fermentation enzyme production. The two microorganisms used are
presented as good producers of cellulases. The results showed the potential of the fungus in
the production of CMCase enzyme, with a maximum of 0.282 UI/mL and the Avicelase
enzyme the maximum value ranged from 0.018 to 0.020 UI/ mL, using only coconut bagasse
as substrate. The Penicillium chrysogenum fungus has showed the best results for CMCase =
0.294 UI/mL, FPase = 0.058 UI/mL, Avicelase = 0.010 UI/mL and Xylanase = 0.644 UI/ mL
enzyme, using coconut bagasse and cashew stem as substrates. The Penicllium chrysogenum
fungus showed enzymatic activities using only the coconut as substrate for CMCase = 0.233
UI/mL, FPase = 0.031 to 0.032 UI/ mL, Avicelase = 0.018 to 0.020 UI/mL and Xylanase =
0.735 UI/ mL. Thus, it can be concluded that the used organisms and substrates have offered
potential for enzyme production processes in a semi-solid cultivation