Characterization of Bacillus Strains Producing Biosurfactants - Environmental Sustainability: Role of Green Technologies - page 172

liquid media composed of different waste products
showed that the best unconventional substrates
for bacteria growth and biosurfactant production
were molasses and brewery effl uents.

fengycin families have well recognized potential
for use in plant disease biocontrol. In our study,
the antifungal activity of Bacillus strains growing
on agro-industrial wastes and their cell-free
supernatants as a source of antifungal agents and
biosurfactants was evaluated. Mycelium growth
inhibition by active Bacillus broth cultures was
evident (Płaza et al. 2012 ). The results demon-
strated the ability of the Bacillus strains grown on
brewery effl uents and molasses to inhibit the
mycelial growth of tested phytopathogenic fungi
(Fig. 3a-c ). Great mycelial inhibition was
observed for the following fungi: B. cinerea A
258, Phomopsis viticola W 977, Septoria carvi K
2082, Colletotrichum gloeosporioides A 259,
Phoma complanata A 233, and Phoma exigua var.
exigua A 175. Inhibition of the mycelial growth
of fungal species by the cell-free supernatants as
sources of antifungal agents was also observed
(Fig. 3d-f ). Fungi appeared more sensitive

7 Bacillus Strains as Biocontrol

Agents

Biological control has emerged as a promising
alternative to chemical pesticides. Currently, the
use of benefi cial micro-organisms (biopesticides)
is considered the most promising method for
environmentally friendly crop-management prac-
tices. Members of the Bacillus genus produce a
variety of biologically active molecules that have
been identifi ed as microbial pesticides, fungi-
cides, or fertilizers (Ongena and Jacques 2008 ;
Pérez-Garcia et al. 2011 ). Among these com-
pounds, cyclic LPs of the surfactin, iturin, and

F i g . 3 Mycelium growth inhibition by Bacillus strains
( a - c ) and cell-free supernatants ( d - f ); ( a ) - inhibition of
Botrytis cinerea A 258 by I ′ -1a strain grown on molasses;
( b ) - inhibition of Colletotrichum gloeosporioides A 259
by I ′ -1a strain grown on brewery effl uents (# 6); ( c ) -
inhibition of Phoma exigua var. exigua A 175 by T ′ -1

strain grown on brewery effl uents (# 4); ( d ) - inhibition of
Botrytis cinerea A 258 by T ′ -1 strain grown on molasses;
( e ) - inhibition of Colletotrichum dematium K 425 by
I ′ -1a strain grown on molasses; ( f ) - inhibition of
Phoma exigua var. exigua A 175 by T-1 strain grown on
molasses