An offshoot of Japanese trader Mitsui & Co has acquired a 15% stake in natural gas distributor Gas Natural Mexico.MIT Gas Mexico will purchase a 13.5% share from Iberdrola Energia for $82 million and a 1.75% holding from the remaining shareholders in GNM for a further $10.8 million.GNM provides natural gas to residential, commercial and industrial sectors in some areas of Mexico.Mitsui