3.2 Methods
3.2.1 Raw materials preparation
3.2.1.1 Corn cob preparation
Corn cobs were collected from local agricultural fields around Chiang Mai, Thailand. Cobs were washed thoroughly and dried under sunlight. After that, dried cobs were ground by a sterile blender. Raw material was stored in the close room, avoiding sunlight and high humidity. When preparing corn cob substrate, dried ground corn cob was took out of the storing room and sieved twice by two different plastic sieves. The sieve with larger holes was placed on top while the sieve with smaller holes was arranged at lower position, and the aluminum tray was placed at the bottom. The biggest dried corn cob pieces ( ̴ 6-7 mm) were kept on the first sieve, letting the rest fall through the second sieve which was only capable of holding medium cob pieces ( ̴ 3 mm). The very fine corn cob (≤ 1 mm) was thus collected in the aluminum tray. Only the medium size dried corn cob was used as the substrate for Monascus cultivation (Figure 3.1).