Optimization of Solid State Fermentation of Mustard (Brassica campestris) Straw for Production of Animal Feed by White Rot Fungi (Ganoderma lucidum)

Abstract

The objective of the experiment was to determine the optimum cultural [moisture levels (55, 60 and 70%), days of fermentation (7, 14 and 21), temperature (25 and 35°C) of incubation)] and nutritional parameters (urea addition (0 and 2%) and variable levels of single super phosphate (0.25 and 0.50% SSP)) for bio-processing of the mustard (Brassica campestris) straw (MS) under solidstate fermentation (SSF) system. The performance of SSF was assessed in terms of favorable changes in cell wall constituents, protein content and in vitro DM digestibility of the MS. Sorghum based inoculum (seed culture) of Ganoderma lucidum to treat the MS was prepared. The 50 g DM of MS taken in autoclavable polypropylene bags was mixed with a pre-calculated amount of water and the particular nutrient in the straw to attained the desired levels of water and nutrient concentration in the substrate. A significant progressive increase in biodegradation of DM (p<0.001), NDF (p<0.01) and ADF (p<0.05) was observed with increasing levels of moisture. Among the cell wall constituents the loss of ADF fraction was greatest compared to that of NDF. The loss of DM increased progressively as the fermentation proceeded and maximum DM losses occurred at 28 days after incubation. The protein content of the treated MS samples increased linearly up to the day 21 th of the incubation and thereafter declined at day 28 th , whereas the improvement in in vitro DM digestibility were apparent only up to the day 14 th of the incubation under SSF and there after it declined. The acid detergent lignin (ADL) degradation was slower during the first 7 days of SSF and thereafter increased progressively and maximum ADL losses were observed at the day 28 th of the SSF. The biodegradation of DM and ADL was not affected by the variation in incubation temperature. Addition of urea was found to have inhibitory effect on fungal growth. The effect of both the levels (0.25 and 0.50) of SSP addition in the substrate, on DM, NDF, ADF, cellulose and ADL biodegradation was similar. Similarly, the protein content and the in vitro DM digestibility remain unaffected affected due to variable levels of the SSP inclusion in the substrate. From the results it may be concluded that the incubation of MS with 60 percent moisture for 21 days at 35°C with 0.25 percent SSP was most suitable for MS treatment with Ganoderma lucidum. Maximum delignification, enrichment in the protein content and improvement in in vitro DM digestibility were achieved by adopting this protocol of bioprocessing of MS.

Selection of white-rot basidiomycetes for bioconversion of mustard (Brassica compestris) straw under solid-state fermentation into energy substrate for rumen micro-organism

“…Similar to present finding, Okano et al (2005) observed higher in-vitro organic matter fermentation (IVOMF) in cedar wood corresponding to greater lignin degradation by different white-rot fungus. Increase in crude protein content of cultured MS is in agreement with earlier reports of protein enrichment on fungal treatment of various straws (Singh et al 1990;Gupta and Singh 1991;Walli et al 1991;Dahia et al 2004;Misra et al 2007). The protein production by the fungus is due to nitrogen that fixed in the mycelia and highly associated with organic matter losses and various factors such as pH, temperature, nature of fungi, type of substrate, aeration, heat etc.…”

“…Sorghum based inoculum (seed culture) of fungus to culture the MS was prepared by growing the fungus (25°C for 7 days) on sterilized sorghum grains supplemented with gypsum (20 g kg )1 ; calcium sulphate) and lime (40 g kg )1 ; calcium carbonate) in glass conical flask (250 ml capacity) closed with cotton plugs. A 50 g DM of MS (2-3 cm) was taken for sterilization by autoclaving, in an autoclavable polypropylene bag (12¢¢ · 8¢¢), mixed with a precalculated amounts of water, nitrogen, phosphorus and sulphur to have desired moisture content and nutrient concentration in the substrate to obtain optimum conditions for maximum delignification, these were standardized in our laboratory (Misra et al 2007). The contents of bags were cooled and inoculated aseptically with spawn (grain culture; 20 g kg )1 ; w ⁄ w) and incubated at 35°C from 7 to 63 days in a biological oxygen demand incubator.…”

Enhanced delignification of lignocellulosic substrates by <i>Pichia</i> GS115 expressed recombinant laccase

“…The energy in the form of cellulose and hemicelluloses is trapped within the lignin matrix owing to the poor digestibility by ruminants. Solid state fermentation using WRF is being continuously employed by many workers for the degradation of crop residues to be successfully used as animal feed [Misra et al, 2007;Tripathi et al, 2008;Sharma and Arora, 2010;Shrivastava et al, 2012]. Many observed an increase in the in vitro DM digestibility of spent straw [Zadrazil, 1997].…”

Biological fungal treatment of olive cake for better utilization in ruminants nutrition in Egypt

“…Therefore, attempts have been made to improve the nutritive value of OC through different chemical agents, but results have been more or less satisfactory (Rowghani et al 2008). Apart from the chemicals, the biological treatment is drawing much attention due to its potential advantages over chemical/physical treatments such as greater substrate and reaction specificity, lower energy requirements, lower pollution generation and higher yields of desired products (Misra et al 2007;Canet et al 2008).…”