The human variant of insulin is produced within the bacteria E. coli or Escherichia coli by the technique of genetic engineering. By producing insulin this way, the cost to patients has dramatically dropped and the problem of immunological side effects have disappeared. Humulin or genetically engineered human insulin is produced by transforming the human insulin gene into E. coli cells and extracting the protein in large fermenters. Rhizobium is a Gram negative, aerobic, motile, non-spore forming symbiotic nitrogen fixing bacterium. It can fix nitrogen only when they are present in the root nodules.Saccharomyces species is a wine yeast and are used in baking and brewing industry respectively.