A survey conducted in various rice mills of Gujarat, India, revealed that around 10–12 kg of residue is produced from
100 kg of raw rice during the polishing process in the mills. This residue accounts for 10–12% of the raw rice produced by farmers. Considering the total rice production in India, the quantity of rice mill processing residue available would be huge. Rice bran if processed within 24 h can be used for the extraction of rice bran oil for edible purpose. However, extraction of rice bran oil within 12–24 h of rice bran production is not always feasible at local rice mills hence, is utilized mostly as cattle feed. Almost 5 million tons of polishing residue is used for rice bran oil extraction and an additional 4 million tons is available for processing, which is currently being used as cattle feed. This additional residue could alternatively
be utilized as a cheap source of carbon for the microbial growth and production of biomolecules of commercial importance.