Sodium chloride (nacl)

The amount of IAA production by B. licheniformis PR2 was quantified using Salkowski's method [35] (link) with UV spectrometers. B. licheniformis PR2 was cultured in a medium containing 0.1 g/L crab shell powder (Purne, Jangseong, Korea), 0.2 g/L Na 2 HPO 4 (Daejung chemicals, Siheung, Korea), 0.1 g/L KH 2 PO 4 (Daejung chemicals, Siheung, Korea), 0.5 g/L NaCl (Daejung chemicals, Siheung, Korea), 0.1 g/L NH 4 Cl (Yakuri pure chemicals, Kyoto, Japan), 0.05 g/L MgSO 4 7H 2 O (Shimakyu's pure chemicals, Osaka, Japan), 0.05 g/L CaCl 2 2H 2 O (Daejung chemicals, Siheung, Korea), 0.01 g/L yeast extract (Purne, Jangseong, Korea), and 0.1 g/L L-tryptophan (Junsei chemical, Tokyo, Japan). The broth was inoculated with 1 mL/L of B. licheniformis PR2 culture (10 7 CFU/mL) and cultured at 130 rpm in a shaking incubator at 30 • C for 10 days. To quantify IAA, samples were collected daily for 10 days. For quantification, 1 mL of supernatant was collected by centrifuging the sample at 12,000 rpm for 10 min at 4 • C. The collected supernatant was mixed with 2 mL of Salkowski's reagent and 0.2 mL phosphoric acid. Subsequently, the reaction mixture was incubated at room temperature under dark conditions for 25 min. The IAA concentration of each sample was measured at 530 nm using a UV-spectrometer. Each experiment was conducted three times.