Study on the effects of organic solvent stress on Bacillus licheniformis S-86

TORRES, SEBASTIAN; PERA, LICIA MARÍA; ASHOK, PANDEY; CASTRO, GUILLERMO RAÚL

Current Topics on Bioprocesses in Food Industry

Asiatech Publishers, INC

Lugar: New Delhi; Año: 2010; p. 1 - 13

The organic solvent-tolerant Bacillus licheniformis S-86 was previously isolated and characterized. In order to establish which stress responses observed in this strain are specific towards organic solvents, a comparative study of the effects of salt stress and 3-methylbutan-1-ol has been investigated. 3-Methylbutan-1-ol or high saline concentration in the media not only reduces cell growth by approximately 80%, but also modifies bacterial size and esterase production. Severe morphological cell changes such as filamentous growth were observed by electron microscopy under both stress conditions. The presence of septa and cellular division was common in the control cells, and in media containing NaCl, but not in the presence of the alkanol, where the division of cytoplasmic membrane was not accompanied by partition of cell wall. But esterase synthesis was boosted approximately two to three times in cultures supplemented with 3-methylbutan-1-ol. Contrarily to that happened in presence of the solvent, esterase production was severely inhibited by more than ten times during cell growth at high NaCl concentrations. Besides, B. licheniformis S-86 is capable of esterified part of 3-methylbutan-1-ol to isoamyl acetate. These findings revealed the presence of specialized mechanisms used by B. licheniformis to overcome different stress conditions