Tata group holding company Tata Sons has picked up 14.68 per cent stake in Praj Industries, a knowledge-based firm engaged in bio-processing and engineering, from promoters for Rs 338.24 crore in open market deals. Tata Sons bought 1.34 crore equity shares in Praj Industries at Rs 252 a piece in a bulk deal on the Bombay Stock Exchange. Praj Industries promoters, Pramod Chaudhari and Parimal Chaudhari, sold 55.06 lakh and 51.25 lakh equity shares. As on June 30, promoters had 28.24 per cent stake in the company.