Solid state fermentation of palm kernel cake by bacillus subtilis

Chin, Hooi Chuan (2007) Solid state fermentation of palm kernel cake by bacillus subtilis. Masters thesis, Universiti Malaysia Sabah.


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It is known that the Palm Kernel Cake (PKC) is one of the potential ingredients of the poultry feed. Inclusion of PKC in poultry feed is very limited due to its high fiber content, low palatability, poor amino acid balance and low digestibility. It is expected that the microbial enzymes would be able to breakdown β-mannan {which is the most abundant fiber in PKC) into simple sugars during solid state fermentation (SSF). This may eliminate the anti-nutritional factors and increase the digestible sugars in PKC which can then be fully absorbed and metabolized by the chickens. In this research, effects of several important parameters during SSF of PKC on the growth of Bacillus subtilis ATCC 3366 were studied. These included the moisture content of PKC, temperature, and pH. In order to understand more about the substrate used for best operation, effect of particle size of PKC on the microbial growth was investigated. The literature review shows that there are no kinetic models to characterize the microbial conversion of PKC, which is essential information for bioreactor design. Hence, growth kinetics of B. subtilis during SSF of PKC was investigated. In current study, SSF operations were carried out in laboratory scale. Parameters monitored on the treated PKC include biomass, reducing sugar content, β-mannananse activity, acid detergent fiber (ADF) content, neutral detergent fiber (NDF) content, and hemicellulose content. From the present studies, it may be concluded that B. subtilis is found to be a potential strain in PKC enrichment. Optimum fermentation conditions observed were 150% moisture content. incubation temperature of 40°C. initial pH of 7, PKC particle size of 850 µm. incubation period of 36 hrs, while inoculum size was 20%. Soluble sugars in treated PKC were increased 5.4 folds; whereas Hemicellulose content was decreased 2.6 folds compared to the untreated PKC. Logistic growth kinetic model described the experimental data of biomass profile satisfactorily. The kinetics parameters Pc and Xm were estimated from the model, which was 0.50 h-1 and 1.82 x 10¹� CFU/gds respectively, at the optimum fermentation conditions. A kinetic equation that is capable of describing the effects of moisture content variations on growth was also developed.

Item Type: Thesis (Masters)
Uncontrolled Keywords: β-Mannanase. Bacillus subtilis. growth kinetics. palm kernel cake (PKC), solid state fermentation {SSF}
Subjects: T Technology > TP Chemical technology
Divisions: SCHOOL > Biotechnology Research Institute (BRI)
Date Deposited: 18 Aug 2014 07:28
Last Modified: 30 Oct 2017 03:24

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