By V.A. Selvi, Senior Principal Scientist, Renewable Energy and Biotechnology, Council of Scientific & Industrial Research-Central Institute of Mining and Fuel Research (CSIR-CIMFR)
India’s population in 2023 is 1,428,627,663, according to Worldometer. This is equivalent to 17.76 per cent of the total world population. Food production in India, as per a 2023 report from the Ministry of Agriculture and Farmers Welfare, amounts to about 329,687,000 tonnes. The food wasted in India, as of 2023, amounts to 74 million tonnes. This wastage of food is generally caused by processing, distribution, agricultural practices, wholesale and retail outlets, hotels, restaurants, households, festivals, and events. The wastage also includes expired and spoiled food. It encompasses a variety of food items at different stages of the supply chain, from production to consumption. These include fruits, vegetables, grains, pulses, dairy products, meat, seafood, bakery, confectionery items, processed foods, cooking ingredients, oils, and various foods and beverages from festivals and events. Various initiatives and practices are being adopted to utilise food waste efficiently and reduce its environmental impact. The modes of recycling food waste include composting, biogas production, conversion to animal feed, food redistribution and donation, food processing and preservation, conversion to animal manure and waste-to-energy. Municipal solid waste (MSW) comes from domestic shops, hotels, schools, hospitals, malls, parks, marriage halls, street food vendors, vegetable and fruit markets, meat and fish markets, etc.
Food waste and MSW are rich sources of cellulose, hemicellulose and starch. The utilisation of these waste biomasses for the production of biofuels is in line with the 2030 Agenda for Sustainable Development set by the UN. Food waste mostly contains carbohydrates, starch, protein, fats and minerals. The dumping of food waste on land may lead to the emission of greenhouse gases and disease-causing pathogens. India’s high demand for energy, coupled with a commitment to sustainability and environmental conservation, has led to a growing emphasis on selecting alternative renewable fuels. India is currently investigating sources for bioethanol, such as leftovers, food waste and municipal waste. These efforts to transform waste into bioethanol are in line with the country’s objectives of managing waste and promoting a circular economy. The Indian government has put in place strategies and programmes to encourage the production of bioethanol. One such initiative is the ethanol blending programme, which aims to mix ethanol with gasoline in order to decrease the usage of fuels and reduce greenhouse gas emissions.
The bio-processing of MSW and food waste into bioethanol is a promising approach towards achieving the target of a 20 per cent blend of ethanol with petrol by 2025. In India, ethanol is produced mainly from starch, molasses, bagasse, etc. Sugarcane is a major crop in India, and molasses, a by-product of sugar extraction, is commonly used for ethanol production. Crops rich in starch, such as corn and sorghum, are used to produce ethanol through fermentation. In addition to molasses, there is an interest in utilising agricultural residues such as bagasse for ethanol production. India has a target of producing 10.16 billion litres of ethanol for blending programmes as well as 3.34 billion litres for other uses by 2025. The current ethanol production capacity is 4.26 billion litres from sugarcane-based distilleries and 2.58 billion litres from grain-based distilleries. Harnessing alternative sources for bioethanol production is very important. Currently, India uses fuel with an 8.5 per cent blend of ethanol. The global bioethanol market was valued at $33.61 billion in 2021. However, the limited availability of raw material for bio-ethanol production is one of the bottlenecks that needs to be resolved to achieve the target of a 20 per cent blend. Food waste and MSW will provide suitable raw materials for bio-ethanol production. Bioethanol is one of the most important renewable fuels, as it could reduce the negative environmental effects of utilising oil fuels and become a sustainable energy carrier in the future.
A great amount of interest is currently being shown in the production of bioethanol as a renewable source of bioenergy by lowering its production cost through the exploitation of low-cost substrates and efficient fermentative microorganisms, and optimisation of the process conditions to obtain maximum yield. CSIR-CIMFR has done research on the feasibility of using food waste and MSW as biomass substrates for bio-ethanol production. The organic part of food waste and MSW accounts for one-third of the total waste, and is considered to be a valuable resource that could be used as raw material for the production of bioethanol.
Research on the utilisation of agricultural waste for bio-ethanol production has shown very promising results worldwide, but there is still a huge gap between the projected and actual bioethanol production at high levels. The use of food by-products and the conversion of food waste are still limited. To make full use of these low-cost, abundant and renewable resources for feasible bioethanol production, several difficulties need to be overcome. These challenges include collection and screening of suitable bio-waste; implementation of cost-effective pretreatment technology; reduction in cost of hydrolytic enzyme production; achieving efficient depolymerisation of bio-waste into fermentable sugars; potential use of microbial enzyme for saccharification and bioethanol production from inexpensive food waste and MSW; and implementation of process to facilitate high bioethanol yield with few by-products, low inhibitor sensitivity and high ethanol tolerance.
The Renewable Energy and Biotechnology Research Group of CSIR-CIMFR has taken initiatives to produce bioethanol from food waste and MSW. MSW contains both organic and inorganic materials. The organic part includes food waste, decayed vegetables, rotten fruits, slaughterhouse waste, paper and cardboard. The inorganic part contains non-biodegradable materials such as metals, construction and demolition debris, electronic waste (e-waste), textiles, rubber, batteries, glass, plastics and ceramics. MSW and food waste are collected, categorised, dried and processed, and bio-ethanol is produced at bench-scale level through fermentation using Saccharomyces cerevisiae.
Bioethanol production from food waste and MSW is an environmentally sustainable approach that can help manage waste while contributing to the production of renewable energy. By raising awareness about the advantages of bioethanol and its potential contribution to energy security, we can foster acceptance among the public. This, in turn, can positively impact policies and market dynamics.
