Biodegradation of Palm Kernel Cake by Cellulolytic and Hemicellulolytic Bacterial Cultures through Solid State Fermentation

Abstract

Four cellulolytic and hemicellulolytic bacterial cultures were purchased from the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Culture (DSMZ) and the American Type Culture Collection (ATCC). Two experiments were conducted; the objective of the first experiment was to determine the optimum time period required for solid state fermentation (SSF) of palm kernel cake (PKC), whereas the objective of the second experiment was to investigate the effect of combinations of these cellulolytic and hemicellulolytic bacteria on the nutritive quality of the PKC. In the first experiment, the SSF was lasted for 12 days with inoculum size of 10% (v/w) on different PKC to moisture ratios. In the second experiment, fifteen combinations were created among the four microbes with one untreated PKC as a control. The SSF lasted for 9 days, and the samples were autoclaved, dried, and analyzed for proximate analysis. Results showed that bacterial cultures produced high enzymes activities at the 4th day of SSF, whereas their abilities to produce enzymes tended to be decreased to reach zero at the 8th day of SSF. Findings in the second experiment showed that hemicellulose and cellulose was significantly (P < 0.05) decreased, whereas the amount of reducing sugars were significantly (P < 0.05) increased in the fermented PKC (FPKC) compared with untreated PKC.

Optimization of bioprocess variables for production of a thermostable and wide range pH stable carboxymethyl cellulase from Bacillus subtilis MS 54 under solid state fermentation

“…Aspergillus fumigatus produced maximum cellulase titer (4 U/mL) after 5 days of SSF on wheat straw, and showed productivity of 0.55 U/mL/h . However, Bacillus amyloliquefaciens , and some other bacteria exhibited maximum cellulase production after 4 days of SSF on palm kernel cake . Thermoascus aurantiacus RCKK produced maximum cellulase yield of 45.3 IU/g after 48 h of SSF on wheat bran with a productivity of 0.94 U/g/h .…”

“…However, thereafter, enzyme yield declined gradually in the beginning (96 h) but relatively rapidly on prolonged fermentation (120-144 h). Agro-industrial residues have been exploited as preferred substrates for the SSF processes using bacterial and fungal strains [10][11][12][13][14][15][16][17][18]. Maize bran is nutritionally rich substrate and adequately supports the growth of process organism.…”

“…Since bacteria need high a W (0.91-0.99) for growth as compared to fungi, therefore, scanty reports are available on successful application of bacteria for SSF [10][11][12]. Although, various agro-residues have been used for SSF [10][11][12][13][14][15][16][17][18], but no reports are available on application of maize bran/almond shells as solid substrate for executing bacterial SSF for cellulase production. Maize bran is nutritionally rich substrate that can support adequate growth of bacteria [3].…”

Solid‐state fermentation of Moringa oleifera leaf meal using Bacillus pumilusCICC 10440

“…In addition to liquid fermentation, we examined the effect of solid‐state fermentation on the release of nutrients from Moringa leaf meal . The soluble protein content of the control group did not substantially change and was approximately 124 mg g −1 .…”

“…The bio‐degradation of cellulose has been studied extensively, and a number of cellulolytic enzymes have been characterized . Commercial cellulases are produced mainly by fungi; however, bacteria have also been considered as robust and versatile enzyme producers due to their high growth rate, stability under extreme conditions, and multienzyme complexes . Bacillus strains are often used in modern biological fermentation technology, as they are non‐toxic and biologically safe .…”