Previous studies on GABA production can be grouped into two categories. As a nutrient source in the food industry, GABA is produced in wild-type Lactobacillus strains isolated from various food sources, such as L. brevis from Chinese paocai and L. paracasei from cheese, yielding several hundred to thousand millimolar GABA with a conversion yield up to 94% in fermentation after optimization [8–14]. Recent advances of fermentative production of GABA using fungal strains, such as Monascus, have achieved up to 13.5 g/L of GABA production yield, which resulted in a lower production yield than Lactobacillus strains [15–18]. Despite these achievements in microbial fermentation, the enzymatic conversion could be advantageous in terms of a higher conversion yield, GABA concentration and its purity for polymer preparation grade.