Sugar mills produce mountains of bagasse, which are either used as cattle feed or burnt to generate electricity.

Researchers from the Department of Chemical Engineering, IIT Bombay, and the Pune-based Vasantdada Sugar Institute have found that it is viable to make lactic acid from bagasse. They found that a lactic acid production facility attached to a sugar mill can have significant economic and environmental benefits.

Bagasse is first pre-treated using sodium hydroxide; then the treated bagasse is hydrolysed with the help of hydrolytic enzymes. Thereafter, the dissolved fractions are used as raw material for bacterial fermentation to produce lactic acid. Excess calcium carbonate is added to the fermentation broth to lower its acidity and extract lactic acid in the form of calcium lactate, which is further purified to produce 99.9 per cent lactic acid. The process also produces gypsum as a by-product, which finds application in the cement industry, says an article provided by IIT Bombay.