2.2. Analysis of extracellular metabolites
The cell growth was monitored by OD600 using a UV–vis
spectrophotometer (Biomate 5, Thermo, NY). The concentrations
of metabolites such as cellobiose, lactose, glycerol, acetate, and
ethanol were determined by HPLC equipped with a refractive index
detector using a Rezex ROA-Organic Acid H+ (8%) column (Phenomenex
Inc., Torrance, CA). The column was eluted with 0.005 N
of H2SO4 at a flow rate of 0.6 mL/min at 50 ◦C.