To compare the growth ability of HY7720 in media containing nitrogen source derived from a plant or animal source, all tested media were prepared based on MRS medium with modifications. The specific recipe was as follows: glucose, 20 g/L; yeast extract, 15 g/L; complex nitrogen source, 10 g/L; dipotassium hydrogen phosphate, 2 g/L; sodium acetate, 5 g/L; diammonium hydrogen citrate, 2 g/L; magnesium sulfate, 0.01 g/L; manganese sulfate, 0.04 g/L; and polysorbate 80, 1 g/L. The following nitrogen sources were tested: soy peptone such as Hy-Soy™ Kosher IPS (Kerry Bio-Science, Norwich, NY, USA) and HSP-349 (The Tatua Co-Operative Dairy Co., Ltd., Morrinsville, New Zealand), Broadbean peptone (Solabia Group, Pantin, France), casein peptone such as Bacto™ Tryptone from casein (Beckton Dickinson, CA, USA) and HCP-321 (The Tatua Co-Operative Dairy Co., Ltd.), and lactoalbumin peptone (Tatua-2016, The Tatua Co-Operative Dairy Co., Ltd.). The growth curves were recorded at 37 °C by measuring absorbance at 600 nm (OD 600 ), and the maximum specific growth rate and the slope of the exponential growth phase (μ max = Δln(OD 600 )/Δt) were determined.