which may be due to the microorganism starts con-
suming the metabolite. At each time surface tension reduction
(ST) was calculated as ST0–STt. The ST of CH culture medium
showed the highest value (ST = 59.5–27 = 32.5 mN/m), followed
by MSM + CH and HH + CH (ST = 55–27 = 28 mN/m) and MSM + HH
(ST = 54.3–27 = 27.3 mN/m). In all cases, ST was 27 mN/m at
day 1 of fermentation. The ST reduction for MSM + HH + CH was
26.8 mN/m. After one day, ST reached a minimum of 26.3 mN/m.
Considering these results, it can be inferred that the strain ZSB10
can use both cellulosic and hemicellulosic hydrolyzates to pro-
duce biosurfactants. In all prior cases, the surface tension reduction
was higher when MSM was used as culture broth for biosur-
factant production, because it only was observed a reduction of
-
ST = 50–32 = 18 mN/m. In all cases,the production of extracellular
biosurfactant was evidenced since a substance can be considered
as biosurfactant when added to distilled water is able to lower the
ST in more than 8 units