Case Studies

Nicotine-Bioremediation

ABIL/ITC/ /FIELD PROJECT/09/15

Introduction
Environmental pollution is one of the major problems in the world. Large quantity of waste containing high concentration of nicotine are generated during the tobacco manufacturing process and all activities that use tobacco. Tobacco (Nicotiana, Solanaceae family) is mainly cultivated in Brazil, China, Cuba, India, and USA. An annual production of 6.7 million tonnes of tobacco has been reported. China is the largest tobacco producer (39.6%) followed by India (8.3%), Brazil (7.0%), and the USA (4.6%). India is the third largest tobacco consumer (275 million) in the world Aerobic Biotaxy India (Pvt) Limited followed by China and USA. It is anticipated that the tobacco industry would produce 3,00, 274 tonnes of nicotine wastes every year. The solid wastes generated usually have an average nicotine content of 18 mg g−1 of dry weight, and have been classified as ‘toxic and hazardous’ by European Union Regulations when the nicotine content exceeds 0·5 mg g−1 dry weight (Civilini et al. 1997;Novotny and Zhao 1999).. Nicotine usually accounts for more than 90% of the whole plant alkaloid fraction in commercial tobacco, Nicotianatabacum.

Nicotine is an additive substance that can lead to nicotine dependence and addictive behaviour in human populations. Nicotine dependence is complex, multidimensional trait that involves psychological, physiological behavioural, and social factors. Nicotine, the primary psychoactive ingredient of tobacco, contributes to physical dependence, by acting on nicotinic acetylcholine receptors in the central nervous system.

Nicotine dissolves easily in water leading to the contamination of the ground water. Hence, the nicotine-contaminated water disturbs the ecological balance of soil and ultimately enters the ground water and then to food chain. Therefore, it is important to remove nicotine from tobacco polluted soil and water.

Physical and chemical methods have been reported to degrade nicotine in the tobacco. These methods are often time-consuming, expensive and involve solvent extraction procedures. Bioremediation is one of the promising methods to clean up polluted environments using microbes Briski et al. reported that aerobic composting is an effective method to reduce 80% of nicotine and 50% of the volume and mass of tobacco solid wastes in 16 d. Meher et al. used a technique called biomethanation that removed 60% of nicotine, 75.6% of chemical oxygen demand, and 80% of biological oxygen demand from the tobacco wastes. Biological method employs a variety of nicotine-degrading bacteria and fungi. These eco-friendly biological methods are extensively used in wastewater treatment due to its high efficiency and low cost. Microbes that degrade nicotine are reported to adapt to polluted environment easily. . The new ABIL system is one of the promising bioremediation system which can degrade the nicotine present in the tobacco completely.

Materials and Methods
Materials
The system with Aerobic Bacterial Generator.

Experimental Procedure
Nicotine is one of the toxic compounds in wastes that accumulate during the processing of tobacco products. Some bacterial strains can tolerate high concentrations of nicotine and metabolize nicotine for growth. Aerobic Bacterial Generator (ABG) is found to be one of the effective process in degrading nicotine, and it has been shown to degrade nicotine completely.

Working:
The system consists of series of tanks and the whole system works automatically. Aerobic Bacterial Generators (ABGs) are set within the first few chambers of the system. These ABGs are inoculated with proprietary mix of microbes which are suitable to degrade the tobacco. For the bioremediation to work there is a requirement of oxygen for which a micro-fine bubble diffuser is installed. These will be pressurized with a linear air pump to provide aeration and mixing. The whole system works on the aeration that is lifting from one tank to other tank continuously. In the process the first few tanks are inoculation tanks then the aeration tanks followed by settlement tanks. The treated material passes on from first chamber to next quiescent chamber for clarification. All the tanks are for the particular purpose, however in the settlement tanks there is no activity of aeration or ABG. In such a situation the microorganisms are settled in the form of gel. This gel is recycled back to the inoculation tank through the airlift recycle pump. If there is presence of any heavy metals and other turbidity in the output water from the system it can be removed through the filters. The final water can be further treated for dye or colour removal and also the heavy metals can be oxidised such that they become non harmful compounds through ozone treatment. The resulting treated effluent will be clear, odourless and nicotine free. Hence the water can be reused. As we discussed we can always arrest the digestion, our intention is only to remove the toxicity and recover the balance bio waste which can be used for multipurpose for pulp and paper industries, packing material etc.