how did eli lilly synthesis the human insulin ? mention one difference between this insulin and the one produced by the human pancreas?

Humulin is a brand name of human insulin produced by Eli Lilly company of America by the help of recombinant DNA technology.The two chains of insulin are separately synthesised in two E.coli. Further, these two chains are isolated from the bacterium and joined by creating disulphide bonds to create human insulin called humulin.