Bacterial Degradation of Textile Dyes - Microbial Degradation of Synthetic Dyes in Wastewaters - page 246

Fig. 1 a Systematic diagram of aerobic bioreactor for formation of bacterial granules. b SEM
images of aerobic granules during the stages of granulation. (i) Cultures before granulation
(2 days) and different stages of granulation (ii) 20 days, (iii) 40 days and (iv) 60 days (Kolekar
2010 )

individual single microbe. Aerobic granules consist of dense microbial consortia
packed with different microbial species and typically contain millions of organisms
per gram of biomass. Thus, treating textile wastewater with environment friendly
aerobic sludge granules could enhance decolorization and degradation of dyestuff,
but it has been rarely documented. Recently, we have developed textile dyes
degrading aerobic sludge granules in a batch reactor and evaluated their potential
for textile dye removal and degradation. It was found that the dye degradation
ef

ciency was very high as compared to individual cultures (Kolekar et al. 2012 ).

3 Factors Effecting Degradation Process

3.1 Microbial Growth and Energy Requirement
for Degradation

The biodegradation ef ciency depends on having the right microbes in the right

place with the right environmental factors for degradation. The microbes (bacteria
or fungi) have the physiological and metabolic potential to biodegrade the synthetic
dyes (Boopathy 2000 ). The degradation process depends on biomass concentration
(population diversity, enzyme activities), substrate (physico-chemical characteris-
tics, molecular structure, and concentration) and a range of environmental factors
like, dissolved oxygen, nitrate concentration, metals, salts, pH, temperature,
moisture content, availability of electron acceptors and carbon and energy sources
(Uddin et al. 2007 ; Phugare et al. 2010 ). Microorganisms are affected by changes in
these parameters and consequently,

their biodegradation capabilities are also