Millets based alternative sustainable cost-effective culture media for microbial growth

Abstract

Millets are a rich source of starch, proteins, lipids, and other nutrients. This study aimed to assess whether millets can be used to formulate sustainable and economically viable culture media, thus potentially replacing the expensive traditional media used for growing microorganisms. Millet samples from Maharashtra, Rajasthan, and Tamil Nadu were assayed for their protein and lipid content. Sorghum vulgare (Jowar), Pennisetum glaucum (Bajra), and Eleusine coracana (Ragi) demonstrated high protein content ranging from 0.63–0.78 mg/ml. Using Thin Layer Chromatography, lipids extracted with hexane were fractionated into several bands and compared against standard fatty acids and cholesterol. Panicum miliaceum (Proso) and Setaria italica (Kang) showed the maximum levels of free fatty acids and cholesterol. Based on the protein, lipid, and nutrient content, millets were used in different compositions to formulate media for growing bacteria and fungi. A mixture of Ragi and Bajra, which serves as calcium and phosphate sources respectively, exhibited zones of phosphate solubilization, thus confirming its potential as an alternative to Pikovskaya medium, which is used to cultivate phosphate- solubilizing bacteria. A mixture of Varai and Rajgira, which serves as carbohydrate and protein sources respectively, showed luxurious growth of fungi, thus confirming its potential as an alternative to Sabouraud’s Agar medium. Phosphate-solubilising bacteria are utilized in biofertilizer formation, thereby contributing to increased agricultural productivity. Besides proving a sustainable, environmentally friendly, and cost-effective alternative, the use of millets for media preparation can boost the agriculture sector and the economy of farmers as well.