Microorganisms engineered to use unconventional sources of nitrogen

A fermentation method of culturing a genetically engineered microbial a cell comprising:

• providing a cell comprising a non-native nucleic acid molecule encoding a melamine deaminase enzyme:
• contacting the cell with a substrate, wherein the substrate comprises a nitrogen-containing fraction and a non-nitrogen-containing fraction and wherein the nitrogen-containing fraction comprises, in an amount from about 10% by weight to about 100% by weight, a nitrogen-containing compound of Formula I, or a salt thereof;
• and
• culturing the cell, wherein the cell can, unlike a cell of the same species that lacks the nucleic acid molecule, metabolize the nitrogen-containing compound and wherein,
• the compound of formula I is
• wherein, independently for each occurrence,
• is a five-, or a six-membered aryl or heteroaryl group;
• R is —OH, —CO2H, —NO2, —CN, substituted or unsubstituted amino, or substituted or unsubstituted alkyl;
• and
• n is 0, 1, 2, 3, 4, or 5.