Therefore, microorganisms have a vital role in the entire processes that they
dynamically maintain the functioning of ecosystem.
13.5.1 Bacteria
There are various studies that report on the degradation of environmental
contaminants by bacteria. Many bacteria have been identified specifically to degrade
the pharmaceuticals (Murdoch and Hay 2015; Marchlewicz et al. 2016). Degradation of pharmaceutical wastewater in a cost-effective and sustainable way can reduce
their harmful impact on natural resources. Degradation process by bacteria is
generally based on two mechanisms. The first one is co-metabolism in which various
kinds of enzymes catalyze the metabolism of other substrate and another one is
metabolic degradation in which organic pollutants are utilized as sole carbon and
energy source (Tiwari et al. 2017). Zeng et al. (2009) described that heterotrophic
bacteria are capable to degrade pharmaceuticals. Pseudomonas aeruginosa TJ1 used
17 β-estradiol (E2) as carbon and energy source for degradation. Stenotrophomonas
maltophilia KB2 has shown the ability to metabolically degrade naproxen
(Wojcieszyńska et al. 2014). Lin et al. (2015) isolated two cefalexin-degrading
bacteria from activated sludge and more than 90% cefalexin degradation is obtained
within a day. Co-metabolism process is done by bacteria which are generally used in
wastewater treatment plant where pharmaceuticals present in even at low concentration (Onesios et al. 2009). Bacterial degradation of ritalinic acid is first time reported
where different microbial strains isolated from environmental matrices
(Arthrobacter sp., Phycicoccus sp. and Nocardioides sp.) used ritalinic acid as C
and N sources (Woźniak-Karczewska et al. 2018). Some other studies related to
bacterial degradation are shown in Table 13.1.
Pure culture of bacteria (Acinetobacter sp. and Microbacterium sp.) can also
degrade antibiotics such as sulfamethoxazole. Some bacteria such as Pseudomonas
sp., Achromobacter denitrificans, etc. need an additional carbon source to degrade
pharmaceuticals (Shourian et al. 2009; Nguyen et al. 2017). The enzymatic treatment
is used for bio-refractory organic compounds which are generally found in
antibiotics and it works effectively even at different concentrations and broad
range of pH, temperature, and salinity. B. subtilis 1556WTNC was proved as most
potent bacteria to grow and produce the β-lactamase and degrade the cephalexin at
pH range 6–7.5 at temperature (30–35
C) (Al-Gheethi and Ismail 2014). Thus, it
found suitable to treat sewage treatment producing β-lactamase that cleaves the βlactam ring to in effective the antibiotic (Akindele et al. 2010).
13.5.2 Fungi
In wastewater treatment process for biotransformation, white rot fungi (WRF) and
their oxidoreductase enzymes have been considered as cost-effective and ecofriendly solution. This group of microorganisms is capable to degrade the pollutants
13 Pharmaceuticals: An Emerging Problem of Environment and Its Removal. . .
279
dynamically maintain the functioning of ecosystem.
13.5.1 Bacteria
There are various studies that report on the degradation of environmental
contaminants by bacteria. Many bacteria have been identified specifically to degrade
the pharmaceuticals (Murdoch and Hay 2015; Marchlewicz et al. 2016). Degradation of pharmaceutical wastewater in a cost-effective and sustainable way can reduce
their harmful impact on natural resources. Degradation process by bacteria is
generally based on two mechanisms. The first one is co-metabolism in which various
kinds of enzymes catalyze the metabolism of other substrate and another one is
metabolic degradation in which organic pollutants are utilized as sole carbon and
energy source (Tiwari et al. 2017). Zeng et al. (2009) described that heterotrophic
bacteria are capable to degrade pharmaceuticals. Pseudomonas aeruginosa TJ1 used
17 β-estradiol (E2) as carbon and energy source for degradation. Stenotrophomonas
maltophilia KB2 has shown the ability to metabolically degrade naproxen
(Wojcieszyńska et al. 2014). Lin et al. (2015) isolated two cefalexin-degrading
bacteria from activated sludge and more than 90% cefalexin degradation is obtained
within a day. Co-metabolism process is done by bacteria which are generally used in
wastewater treatment plant where pharmaceuticals present in even at low concentration (Onesios et al. 2009). Bacterial degradation of ritalinic acid is first time reported
where different microbial strains isolated from environmental matrices
(Arthrobacter sp., Phycicoccus sp. and Nocardioides sp.) used ritalinic acid as C
and N sources (Woźniak-Karczewska et al. 2018). Some other studies related to
bacterial degradation are shown in Table 13.1.
Pure culture of bacteria (Acinetobacter sp. and Microbacterium sp.) can also
degrade antibiotics such as sulfamethoxazole. Some bacteria such as Pseudomonas
sp., Achromobacter denitrificans, etc. need an additional carbon source to degrade
pharmaceuticals (Shourian et al. 2009; Nguyen et al. 2017). The enzymatic treatment
is used for bio-refractory organic compounds which are generally found in
antibiotics and it works effectively even at different concentrations and broad
range of pH, temperature, and salinity. B. subtilis 1556WTNC was proved as most
potent bacteria to grow and produce the β-lactamase and degrade the cephalexin at
pH range 6–7.5 at temperature (30–35
C) (Al-Gheethi and Ismail 2014). Thus, it
found suitable to treat sewage treatment producing β-lactamase that cleaves the βlactam ring to in effective the antibiotic (Akindele et al. 2010).
13.5.2 Fungi
In wastewater treatment process for biotransformation, white rot fungi (WRF) and
their oxidoreductase enzymes have been considered as cost-effective and ecofriendly solution. This group of microorganisms is capable to degrade the pollutants
13 Pharmaceuticals: An Emerging Problem of Environment and Its Removal. . .
279