Chitin utilization in serum-free medium containing a lipid supplement. Serum-free BSK-II was supplemented with a lipid mixture. Wild-type cells in late-log phase were diluted to 1.0 × 105 cells ml-1 in the absence of free GlcNAc and supplemented with the following substrates: 1.5 mM GlcNAc (closed circle), No addition (open circle), 75 μM chitobiose (closed triangle) or 25 μM chitohexose (closed square). Cells were enumerated daily by darkfield microscopy. This is a representative experiment that was repeated three times.