Abstract
Microbial β-(1→3)-glucans are polysaccharides of biological and technological in-terest whose production depends strongly on strain and culture conditions. This study characterized the temporal relationship between bacterial growth and aniline-blue re-activity in Alcaligenes faecalis A12C under growth and fermentation conditions. Growth, viability, and β-(1→3)-glucan-associated signals were monitored over 96 h using spec-trophotometric, microbiological, and microscopic approaches. In growth culture me-dium (GCM), OD600 increased after 24–30 h and reached approximately 2.4 at 72 h, coinciding with the highest viable count (2.49 × 10²¹ CFU/mL). Aniline-blue coloration became clearly detectable after approximately 30 h and persisted through 96 h, when microscopy showed blue staining associated with bacterial cells. In fermentation culture medium (FCM), OD600 increased progressively to approximately 2.8 at 96 h, whereas viable counts followed a distinct temporal profile. Aniline-blue reactivity increased during early fermentation and remained stable at an A610 of approximately 1.0 from 24 h onward. The divergence among OD600, viable counts, and aniline-blue reactivity in-dicates that bacterial proliferation and development of the aniline-blue-reactive signal followed distinct temporal patterns. These findings characterize this temporal rela-tionship in A12C cultures, although chemical and structural characterization is required to determine whether the detected polymer corresponds to curdlan.