Fermentation conditions
The fermentation was carried out in 250 ml conical flasks containing 50 ml medium. The substrate was sterilized at 121 C for 15 min. After cooling, the medium was inoculated with the appropriate ratio of (+) and () mating type of B. trispora in order to obtain a ratio of 1:1 (1.5 105/1.5 105 spores/ml), 1:2 (1.5 105/3.0 105 spores/ml), 1:5 (1.5 105/7.5 105 spores/ ml), and 1:10 (1.5 105/1.5 106 spores/ml) of (+)/( ), respectively. The flasks were incubated at 26 C in a rotary shaker incubator (Lab Line Orbit-Environ Shaker, Lab-Line Instr., Melrose Park, IL, USA) at 250 rev/min.