**3.1 Microorganisms**

Microorganisms used as soybean fermentation starters include bacteria, molds and yeasts. The first procedure for soybean fermentation is the preparation of Qu (in Chinese) or called koji (in Japanese). Koji is a source of microorganisms and their enzymes for converting the carbohydrates and proteins into sugars, peptides, and amino acids, etc. contained in the materials. The nutrients which were produced through the action of these enzymes will be used by yeasts and lactic acid bacteria during further fermentation period (Abe et al., 2006).
