Diacetylchitobiose/Chitobiose, a dimer of β(1,4) linked N-acetyl-D glucosamine, is used as an alternative source of N-acetylglucosamine by some bacteria.
[1] It is used in fermentation research to study, differentiate and characterize chitobiose transporter systems and enzymes such as β-N-acetylglucosaminidase(s) and chitobiose phosphorylase(s).
[2][3]