reported (Bessa et al. 2017; Sharma et al. 2020). Streptomyces spp. demonstrated the
biotransformation of Clofibric acid under submerged conditions due to co-metabolic
pathway.
13.4.1 Aerobic Biodegradation
According to the National Research Council “Aerobic biodegradation is the degradation of compounds by microorganisms in the presence of oxygen”. In aerobic
biodegradation for the transformation of organic components to simpler products,
the microbe converts oxygen to water. Oxygen acts as an electron acceptor under the
aerobic conditions. In aerobic biodegradation process, the pollutant degradation rate
is habitually inhibited by the presence of oxygen which is provided by the atmospheric diffusion or dissolved in and carried by water. The atmospheric diffusion of
oxygen into water and soil slows down and water solubility of oxygen is also low.
Recently, emerging contaminants such as pharmaceuticals and personal care
products have been primarily focused on aerobic biodegradation. Aerobic degradation is more suitable method rather than anaerobic degradation (Ghattas et al. 2017).
To examine the sorption and degradation of bisphenol A at g/L range by aerobic
activated sludge lab-scale batch experiments were conducted. BPA elimination in
the aerobic activated sludge system was determined by sorption on activated sludge
and biodegradation (Zhao et al. 2008). Aerobic degradation of tylosin was
performed in water and soil to examine its environmental fate. It was degraded by
a half-life of 200 days in light and water (Hu and Coats 2007). Complete elimination
of naproxen was obtained within 14 days by addition of external carbon source under
aerobic conditions (Lahti and Oikari 2011). Construction of treatment wetland for
wastewater treatment, the aerobic conditions of water and soil column plays a major
role to enhance the treatment effectiveness for pharmaceuticals. As compared to
anaerobic conditions the degradation of specific compounds was higher in aerobic
conditions. Under aerobic conditions ibuprofen, DEET and gemfibrozil usually had
the half-life about 20 days (Conkle et al. 2012). Deng et al. (2016) reported that for
the degradation of sulfadiazine, two aerobic bacterial strains D2 and D4 of genus
Arthrobacter were isolated from sulfadiazine containing activated sludge. For strain
D2 half-life time for the degradation was 11.3 h and for D4 it was 46.4 h. For aerobic
degradation of sulfamethoxazole activated sludge was used as sole carbon and
nitrogen source and microbes utilized it for their growth (Müller et al. 2013). Thus
aerobic biodegradation has been proved as convenient and sustainable method to
degrade pharmaceutical compounds in environmental matrices.
13.4.2 Anaerobic Biodegradation
The process for anaerobic digestion is usually employed to treat settled and semiliquid sludge. Anaerobic biodegradation is regarded as fermentation process having
four steps such as hydrolysis, acidogenesis, acetogenesis, and methanogenesis which
13 Pharmaceuticals: An Emerging Problem of Environment and Its Removal. . .
275
biotransformation of Clofibric acid under submerged conditions due to co-metabolic
pathway.
13.4.1 Aerobic Biodegradation
According to the National Research Council “Aerobic biodegradation is the degradation of compounds by microorganisms in the presence of oxygen”. In aerobic
biodegradation for the transformation of organic components to simpler products,
the microbe converts oxygen to water. Oxygen acts as an electron acceptor under the
aerobic conditions. In aerobic biodegradation process, the pollutant degradation rate
is habitually inhibited by the presence of oxygen which is provided by the atmospheric diffusion or dissolved in and carried by water. The atmospheric diffusion of
oxygen into water and soil slows down and water solubility of oxygen is also low.
Recently, emerging contaminants such as pharmaceuticals and personal care
products have been primarily focused on aerobic biodegradation. Aerobic degradation is more suitable method rather than anaerobic degradation (Ghattas et al. 2017).
To examine the sorption and degradation of bisphenol A at g/L range by aerobic
activated sludge lab-scale batch experiments were conducted. BPA elimination in
the aerobic activated sludge system was determined by sorption on activated sludge
and biodegradation (Zhao et al. 2008). Aerobic degradation of tylosin was
performed in water and soil to examine its environmental fate. It was degraded by
a half-life of 200 days in light and water (Hu and Coats 2007). Complete elimination
of naproxen was obtained within 14 days by addition of external carbon source under
aerobic conditions (Lahti and Oikari 2011). Construction of treatment wetland for
wastewater treatment, the aerobic conditions of water and soil column plays a major
role to enhance the treatment effectiveness for pharmaceuticals. As compared to
anaerobic conditions the degradation of specific compounds was higher in aerobic
conditions. Under aerobic conditions ibuprofen, DEET and gemfibrozil usually had
the half-life about 20 days (Conkle et al. 2012). Deng et al. (2016) reported that for
the degradation of sulfadiazine, two aerobic bacterial strains D2 and D4 of genus
Arthrobacter were isolated from sulfadiazine containing activated sludge. For strain
D2 half-life time for the degradation was 11.3 h and for D4 it was 46.4 h. For aerobic
degradation of sulfamethoxazole activated sludge was used as sole carbon and
nitrogen source and microbes utilized it for their growth (Müller et al. 2013). Thus
aerobic biodegradation has been proved as convenient and sustainable method to
degrade pharmaceutical compounds in environmental matrices.
13.4.2 Anaerobic Biodegradation
The process for anaerobic digestion is usually employed to treat settled and semiliquid sludge. Anaerobic biodegradation is regarded as fermentation process having
four steps such as hydrolysis, acidogenesis, acetogenesis, and methanogenesis which
13 Pharmaceuticals: An Emerging Problem of Environment and Its Removal. . .
275