2.1. Bacterial cultures
Bacterial cultures were collected samples of water of the tank
(10 mL) and of the conical cylindrical decanter (10 mL) with the aid
of 15 mL sterile test tubes from a super-intensive bio floc L. vannamei
cultivation system. The isolation and selection of bacteria of the genus
Bacillus sp. were done following a method adapted from Travers et al.
(1987) . After isolation, these organisms were grown on Caldo L
(composition: 10 g tryptone, 5 g yeast extract and 3 g NaCl in 1 L of distilled water) and were given a heat shock until sporulation (Polanczyk
et al., 2004). Colony-forming units with Gram-positive spore bacilli
features con firmed by the method described by Wirtz –Conklin (apud
Hamouda et al., 2002) were selected with the aid of malachite green.