## 3 Use of Microbial Agents in Remediation System  
### White-Rot Fungi in Solid-State Cultivation  
The dye-adsorbed agricultural residues that resulted after the above dye-removal experiments needed safe disposal into the environment. Several experiments were conducted using dye-adsorbed material, and the researchers found that these dye-adsorbed substrates could be used in solid-state fermentation (SSF) cultivating two strains of white-rot fungi-_Coriolus versicolor_ and _Phanerochaete chrysosporium_[12; 13]. Both fungi grew well in the form of thick mycelial growth in SSF without any inhibition due to presence of dye chemicals and produced a fungal-biomass with a protein content of 19, 23, 50 g and 16, 25, 35 g, respectively, per 100 g dry weight of three substrates used in SSF: wood chips, corncob shreds, and wheat straw (Figures 1 and 2). [PERSON] and [PERSON], [13] followed a strict screening strategy for the selection of most effective microorganism for dye-degradation employing few white-rot fungi in SSF. The process was studied for the treatment of an actual effluent generated from one Ireland-based American textile industry. After the screening process, one fungus, _Bjerkandera adusta_, was investigated in detail for its ability to grow on solid substrate adsorbed with dye-molecules. Fungal mycelium produced in solid-state fermentation enriched the nutritional quality of residual barley husks. Project work included the detailed study of important parameters, including SSF-medium composition, requirements of moisture, enzymes produced by fungi during SSF, and the protein content in fermented barley husk covered with fungal mycelium biomass. Experiments were further conducted to optimise the protein-enrichment of SSF material by supplementing the process with nitrogen at a 20:1 C:N ratio [14]. This approach provided preliminary findings and suggestions for the treatment of textile effluent, and the bioconversion of utilised agricultural substrates as dye-adsorbed material into protein-enriched mass after fungal growth for their safe recycling as a soil conditioner when mixed with soil. A method, which was previously optimised [15] for the extent of dye desorption from dye-adsorbed solid particles, was used to measure the degradation of dyes as a result of fungal enzyme activity during the period of SSF. Using this method, fungal strain _B. adusta_ was reported to decolourise the synthetic dye up to 53% in SSF performed at a moisture content of 80-85%. The fermented mass due to fungal-growth was enriched with protein and analysed as 229 g/kg dry weight of substrate used in fermentation. After SSF, the fermented mass of dye-adsorbed residues was analysed for actual dyes degradation by fungi and content of dyes still left adsorbed on fermented substrates. There was no standard method for the quantitative analyses of dyes contained in solid agricultural substrates after microbial degradation; therefore, researchers [15] studied the extraction of colour from SSF-material, which could be analysed quantitatively. Two types of preparation of solvents--A consisted of methanol + chloroform + water in equal ratio; B consisted of 1:1 methanol and water--were tested to wash  
Figure 1: Recycling of agricultural residual material for textile dyes-removal from wastewater, and bioremediation using bioagents. (Picture taken by author [PERSON] from lab experiment, not published anywhere). Figure 2: Growth of two white-rot fungi _Phanerochaete chryssosporium_ and _Coriolus versicolor_ in the fermentation of dye-adsorbed substrates. (Picture taken by author [PERSON] from lab experiment, not published anywhere). out the dyes adsorbed onto substrates' particles. This method was optimised for the analyses of the percentage of dyes degraded during fungal growth in SSF. Apple pomace, barley husk, and corncob were soaked separately in individual solutions of five separate dyes, and in a synthetic textile-effluent prepared by mixing equal ratio of all five dyes, which were used for the adsorption of dyes on substrates' particles.