2. Materials and methods
2.1. Bacterial strains and culture conditions
The Lactobacillus strains used in this study are listed in Table 1.
Strains of Lactobacillus casei subsp. casei, Lactobacillus salivarius
subsp. salicinius, and Lactobacillus fermentum were obtained from
the China Center of Industrial Culture Collection (CICC). Lactobacillus
plantarum, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus
acidophilus, and L. delbrueckii subsp. lactis were obtained
from the China General Microbiological Culture Collection
(CGMCC). Lactobacillus rhamnosus GG (ATCC 53103) was obtained
from the American Type Culture Collection (ATCC) and LGG was
used as the reference strain. These strains were chosen in the
present work because they are extensively used in fermented food.
All lactobacilli strains were cultured in de Man, Rogosa, and Sharpe
broth (MRS; Qingdao Hope Bio-Technology Co., Ltd, China) or on
MRS agar plates (MRS broth supplemented with 1.5% agar) under
anaerobic conditions (85% N2, 10% H2 and 5% CO2) at 37 C for 18 h
or 48 h, respectively.