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Application of
acid-hydrolyzed cassava (Manihot esculenta) and
cowpea (Vigna unguiculata) for the production of
yeast (Saccharomyces cerevisiae)
Nyerhovwo J. Tonukari* and Linda I. Osumah
Department of Biochemistry, Faculty of Science,
Delta State University, P. M. B. 1, Abraka, Delta State,
Nigeria.
*Corresponding author. E-mail:
tonukari@gmail.com.
Accepted
7 April, 2010. |
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Much
progress has been made in the cultivation and production of
cassava (Manihot esculenta) and cowpea (Vigna
unguiculata) in Nigeria. In the present study,
investigation was carried out on the possibility of using
cassava flour as a source of glucose as well as cowpea as
source of nitrogen in the production of yeast. Acid
hydrolysis (using dilute H2SO4) of
cassava and cowpea was undertaken to release the sugars and
amino acids. The pH of the growth medium using hydrolyzed
cassava as carbon source and cowpea as nitrogen source was
varied from pH 2.5 - 6.5. The results obtained show that pH
6.5 gave optimum yeast biomass. The hydrolyzed cassava was
also varied in the growth medium. The result obtained shows
that increased concentrations of acid-hydrolyzed cassava
increased yeast biomass, indicating that hydrolyzed cassava
is a good carbon source of glucose for yeast production. It
was also observed that yeast biomass using acid hydrolyzed
cowpea extract as nitrogen source was high. This is due to
the fact that cowpea contains 66.35% of carbohydrate in
addition to about 25% protein and hence a good source of
carbon and nitrogen in the culture medium. The residual
glucose concentration of the yeast culture for each medium
was also determined. The result obtained indicates that with
increased yeast biomass, there was significant decrease in
the residual glucose. Also, there was a significant decrease
in pH of the culture media following yeast culture; the
culture media tends to be acidic after yeast culture.
Therefore, yeast can be produced using acid hydrolyzed
cassava flour as carbon source with cowpea as nitrogen
source.
Key
words:
Cassava, cowpea, yeast, acid hydrolysis, glucose, nitrogen
source. |
