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Waste Water Treatment and Reutilization 2011 Part 4

Tham khảo tài liệu 'waste water treatment and reutilization 2011 part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 70 Waste Water - Treatment and Reutilization Some white-rot fungi used in the biodegradation decolourization studies and their most commonly expressed enzyme activities are presented in Table 3. The data are collected from numerous research articles where the cultivation conditions varied and it is thus possible that an activity would or would not occur under different cultivation conditions esp. nitrogen contents Knapp 2001 Singh 2006 . 4.2 Mechanisms of fungal dye degradation and decolourization The mechanisms of fungal dye decolourization and degradation are listed in Table 4. The accumulation of chemicals with the microbial biomass is termed biosorption and can take place on living or dead biomass. Waste and or dead microbial biomass can be used as an efficient adsorbent especially if containing a natural polysaccharide chitin and its derivative chitosan in the cell walls. Chitosan a cell wall component of many industrially useful fungi has a unique molecular structure with a high affinity for many classes of dyes Joshi et al 2004 . Adsorption biosorption Biodegradation Adsorption and biodegradation Mineralization Utilization as carbon source Table 4. Mechanisms of fungal dye degradation and decolourization It is known that most of the white-rot fungi produce at least two of the three highly nonspecific enzymes like LiP MnP and Lac which enable the generation of free radicals when conducting a variety of reactions Pointing 2001 Knapp 2001 . The structure of dyes strongly influences their degradability by pure cultures and isolated enzymes. Numerous data about biodegradation of various synthetic dyes with selected white-rot fungi have been published. Nevertheless a limited number of data are available on systematic studies about the relation between the structure and biodegradability esp. for commercial dyes with a complex structure. According to the above mentioned in the presence of biomass in the dye solution it has to be distinguished between the dye .