Bioremediation is a technology that ‘treats’ environmental pollution using microbes, plants or their by-products. It helps in removing xenobiotic and recalcitrant pollutants through physical or chemical methods. Pharmaceutical industry releases large quantities of recalcitrant pharmaceutical by-products. Additionally, farming and municipal wastes contribute to the pollution. Although pharmaceutical products are biologically active, they are non-biodegradable and recalcitrant in nature, which makes pharmaceutical pollution difficult to be rid of using conventional methods (1).
Furthermore, compounds such as antibiotics and hormones in the environment affect bio diversity and functioning of natural microbiota of the soil. Furthermore, pharmaceutical pollution causes disturbance in ecological function and soil fertility (2,3). Moreover, pharmaceutical pollutants can also travel up the food chain and affect aquatic and terrestrial organisms, including humans (4). Nevertheless, researchers have explored the possibility of using biological systems in mitigating pharmaceutical pollution, especially since physio-chemical methods have failed to efficiently remove pharmaceutical waste products (5,6).
Major pharmaceutical pollutants
Pharmaceutical pollution includes raw materials, end products and by-products involved in manufacturing of wide range of products (7). As a case in point, the table below shows type and class of various pollutants released by pharmaceutical industries.
|Types of Pharmaceutical Pollutants|
|Antibiotics||Hormones and steroids|
Table: List of effluents from Pharmaceutical industries (7).
Impact of pharmaceutical pollution
Excess antibiotics enter the environment either through human waste or during the manufacturing processes. Antibiotics enter soil, municipal waters, ground waters, ultimately reaching the plants and herbivores (8). More importantly, antibiotics destroy the natural ecosystem of soil and aquatic environment and select resistant strains. Another pharmaceutical product, analgesics (painkillers and pain relievers) also affect the natural ecosystem (9). For example, Diclofenac and Ibuprofen, have been reported to have negative impacts on crops and plants, namely affecting their growth and development (10).
|Pharmaceutical agents||Harmful effects|
|Fluoxetine||Alters estradiol levels in fish and sexual dysfunction in humans.|
|Diclofenac, Ibuprofen etc.||Renal impairment of fish, birds and humans; also death of vultures.|
|Ethinyl estradiol||Effect the fertility and development of fish, reptiles and other aquatic invertebrates.|
|Cytotoxins||Produces reproductive toxins in aquatic animals and tumors in plants.|
|Enrofloxacin and other antibiotics||Evolution of antibiotic drug resistant pathogenic microbes leading to ineffectiveness.|
|Chlorpyrifos Atrazine||Susceptibility to Viral infections in humans and other animals decreases.|
Table: Pharmaceutical agents and their harmful effects (Source: Randhawa & Kullar, 2011).
Besides antibiotics and analgesics, hormones are the largest producers of wastes from pharmaceutical industries. Additionally, compounds such as Cyproterone Acetate, Letrozole, Steroids, Contraceptives and others are reported to have been found in waste waters released by the pharmaceutical industries (6). These hormones are accumulated by plants which cause mutations and are also carcinogenic, hampering their growth phenotypically and genetically (11). Another worrying contaminants is metal, such as iron, chromium, lead, zinc, nickel, cadmium, found in pharmaceutical wastes in alarming levels of 0.05-11 mg/l (12). These metals when accumulated by plants affect water transport, nutrient uptake from the soil and the rhizosphere (13,14).
Role of microbes in bio-remediation of pharmaceutical pollution
Biological systems are efficient in converting recalcitrant and xenobiotic pharmaceutical drugs to less toxic forms or even leading to complete mineralisation. In fact, it has been reported that certain strains of microorganisms have the potential to use pharmaceutical wastes as their carbon source (15). Thus, bio-degradation of waste is vital and depends on a number of factors, such as structure of the compound, toxicity, concentration levels, environmental conditions during degradation, efficiency of the microbes to be used and presence of other compounds and their concentrations (16). In case of pharmaceutical products, naturally occurring microbes have the capability of metabolizing the compounds but lack access to them as well as nutrients. This coupled with low abundance of such strains significantly affect their remediation capabilities (17).
It has to be emphasized that pharmaceutical pollutants can be biodegraded using conventional biological technologies such as Aerobic and Anaerobic treatment, fungal treatment, bacterial treatment, phytoremediation and membrane bioreactors (18). These treatments lead to significant reduction in Chemical oxygen demand (COD), Total Suspended Solids and also Total Dissolved Solids (TDS). Additionally, cow dung has been used in the bio degradation of pharmaceutical compounds (4)
Mode of action
Literature review showed that a wide range of organisms have been found to actively metabolize pharmaceutical products of which microbes are prominent. Thus, the table below lists species that can be used for bio remediation of pharmaceutical waste.
|Type of Microorganism||Examples||Target Pollutants|
|Bacteria||Mixed Bacterial Cultures,
Clostridium sp. etc
|Phenols, Cresols, catechol, sulphates, resorcinols, suspended solids, Pentachlorophenols, Organic compounds, Diclofenac, Ibuprofen etc|
Penicillium sp. etc
|Phenols, organic and inorganic compounds etc|
tomato hairy root cultures,
|Toxic and Heavy metals, Phosphorous, Phenols etc.|
Table: Organisms capable of bioremediation of pharmaceutical pollutants (18).
Studies on microbial species in bio remediation have focused on their effect on reducing COD and Biological Oxygen Demand (BOD) removal, rather than the mode of action or the enzymes involved. Further studies have also shown higher efficiency of anaerobic reactors in treating pharmaceutical waste water (19). For example, Rodriguez-Martinez et al. (2005) showed 90% COD in Penicillin G containing pharmaceutical wastewater was removed using Up-flow Anaerobic sludge reactor (20). In another study, anaerobic baffled reactors were used to treat ampicillin and Aureomycin waste water, leading to 16-30% partial degradation. Additionally, for the case of analgesics, bio degradation of Diclofenac in a bioreactor is shown in a flow chart, explaining the mode of microbial action for bio remediation (21). There were also similar studies that looked at bioreactors. However, there is a lack of focus on identification of species responsible for bio remediation of specific pharmaceutical compound.
Need for optimal re-mediating mixtures
Various pharmaceutical residues have been detected in the environment, whereby these pollutants affect aquatic organisms, terrestrial organisms, humans, plants and also the microbiota of the soil. Thus, elimination and degradation of these elements are very important as they are toxic and mutagen and whereby, these can be achieved using microbes, plants and their metabolites. Further studies have been conducted on efficiency of bioreactors in achieving COD and BOD removal, along with degradation of pharmaceutical products. However, it is proven that anaerobic reactors efficiently re-mediate these recalcitrant compounds. This point towards a dire need for isolating species responsible for degrading specific compounds in addition to designing optimal consortium capable of re-mediating mixture of pharmaceutical pollution.
- Kapoor D. Impact of pharmaceutical industries on environment, health and safety. 2015;2(4).
- Ding C, He J. Effect of Antibiotics in the Environment on microbial polutions. 2015;97(22):9637–46.
- Shalini K, Anwer Z, Sharma PK, Garg VK, Kumar N. A review on pharma pollution. Int J PharmTech Res. 2010;2(4):2265–70.
- Randhawa GK, Kullar JS. Bioremediation of Pharmaceuticals, Pesticides, and Petrochemicals with Gomeya/Cow Dung. ISRN Pharmacol. 2011;2011:1–7.
- Mansour H Ben, Mosrati R, Barillier D, Ghedira K, Chekir-Ghedira L. Bioremediation of industrial pharmaceutical drugs. Drug Chem Toxicol. 2012;35(3):235–40.
- Eckert V, Bensmann H, Zegenhagen F, Weckenmann J, Sörensen M. Elimination of hormones in pharmaceutical waste water. Pharm Ind. 2012;74(3):487–92.
- Chander V, Singh P, Sharma B, Upadhyaya K, Kumud R. Environmental and Health Hazards due to Pharmaceutical Effluents. Pharm Rev Res. 2014;4(2):100–3.
- Abhilash NT. Pharmaceuticals in Environment : A review on its effect. Res J Chem Sci. 2012;2(1):103–5.
- Dhanapal LP, Morse AN. Effect of analgesics and their derivatives on antibiotic resistance of environmental microbes. Water Sci Technol. 2009;59(9):1823–9.
- Patneedi CB, Prasadu KD. Impact of pharmaceutical waste on human life and environment. Rasayan J. 2015;8(1):2008–11.
- Küster A, Adler N. Pharmaceuticals in the environment: scientific evidence of risks and its regulation. Philos Trans R Soc Lond B Biol Sci. 2014;369(1656):20130587 .
- Singh A, Ramola B. Environmental & Analytical Toxicology Heavy Metal Concentrations in Pharmaceutical Effluents of Industrial Area of Dehradun (Uttarakhand), India. J Env Anal Toxicol. 2013;3(3):140–5.
- Chibuike GU, Obiora SC. Heavy metal polluted soils: Effect on plants and bioremediation methods. Applied and Environmental Soil Science. 2014.
- Wang WX. Prediction of metal toxicity in aquatic organisms. Chinese Science Bulletin. 2013. p. 194–202.
- Kartheek BR, Maheswaran R, Kumar G, Banu GS. Biodegradation of Pharmaceutical Wastes Using Different Microbial Strains. 2011;2(5):1401–4.
- Misal SA, Lingojwar DP, Shinde RM, Gawai KR. Purification and characterization of azoreductase from alkaliphilic strain Bacillus badius. Process Biochem. 2011;46(6):1264–9.
- Edwards SJ, Kjellerup B V. Applications of biofilms in bioremediation and biotransformation of persistent organic pollutants, pharmaceutical pollution/personal care products, and heavy metals. Appl Microbiol Biotechnol. 2013;97(23):9909–21.
- Rana, Singh R, Singh P, Kandari V, Singh R, Dobhal R, Gupta S. A review on characterization and bioremediation of pharmaceutical industries ’ wastewater : an Indian perspective. Appl water Sci. 2014.
- Chelliapan S, Sallis PJ. Anaerobic biotechnology for pharmaceutical wastewater treatment. Res J Pharm Biol Chem Sci. 2013;4(4):1255–61.
- Rodríguez MJ, Garza GY, Aguilera CA, Martínez ASY, Sosa SGJ. Influence of Nitrate and Sulfate on the Anaerobic Treatment of Pharmaceutical Wastewater. Eng Life Sci. 2005;5(6):568–73. Available at : http://onlinelibrary.wiley.com/doi/10.1002/elsc.200520101/abstract.
- Cherik D, Benali M, Louhab K. Occurrence, ecotoxicology, removal of diclofenac by adsorption on activated carbon and biodegradation and its effect on bacterial community: A review. World Sci News. 2015;16:116–44.
- Langenhoff A, Inderfurth N, Veuskens T, Schraa G, Blokland M, Kujawa-Roeleveld K, et al. Microbial removal of the pharmaceutical compounds ibuprofen and diclofenac from wastewater. Biomed Res Int. 2013;2013.