Saudi Basic Industries Corp (SABIC) said it started on April 1 commercial production at a 2.8 million ton expansion of a petrochemical joint-venture with Japanese partners including Mitsubishi. In a statement posted on the bourse website, SABIC - the world's biggest chemical firm by market value - said the third expansion phase of Sharq would bring the overall capacity of the complex to 5 million tons per year. Sharq is a joint venture equally owned by SABIC and SPDC Ltd, a Japanese consortium led by the government of Japan and a consortium of companies led by Mitsubishi. The Gulf is undergoing massive capacity expansion in petrochemicals and will soon account for a lion's share of world's ethylene production, investment bank Alpen Capital has said in its new report. A growing shortage of ethane besides delay and cancellation of projects are two factors adversely impacting the petrochemical sector in the region, it said.