Heard back from Ivo Baldani about the origin of the media name, LGI.
"LGI medium is a modification of LG medium developed by Lipman (1904). ref. Lipman, J.G. Soil bacteriological studies. Further contribution to the physiology and morphology of the mebers of the Azotobacter group. Report of the New Jersey State Agricultural Sperimental Station, v. 25p. 237-289, 1904. As far I learn from Dr. Johanna Dobereiner the original medium was named LG. She included I ( from Ivo) because I modified the medium to isolate Azospirillum amazonense."