d(GC) - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and Pharmacy
Vol. 6 (2) 190-195 April 2012, ISSN 0973-8916 (Print), 2230-7303 (Online)
temperature optimization, growth as well as
enzyme production was estimated at various
temperatures viz. 30°C, 35°C, 37°C, 40°C, 42°C,
45°C and 50°C. For checking induction effect of
xylan on xylanase production, two 500 ml
capacity Erlenmeyer flasks were deployed
marked as control and experimental. In each
flask, 200 ml of Emerson medium was put and
autoclaved. In experimental flask, 1% xylan was
also added. Each flask was inoculated using 2%
(4 ml) inoculum. Both the flasks were incubated
in an orbital shaker at 37 o C with a speed of 200
rpm. From each flask, 20 ml suspension was
withdrawn aseptically at intervals of 12 hours.
Each withdrawn aliquot was centrifuged at 10,000
x g for 15 minutes at 0 to 4°C in a cooling
centrifuge and the supernatant was analyzed for
xylanase activity. The effect of different
concentrations of xylan on enzyme production
was also observed using different concentrations
of xylan viz. 0.5%, 1%, 2%, 3%, 4% and 5%.
One control was also run with 0 % xylan. All the
flasks were incubated in an orbital shaker at 37 o C
with a speed of 200 rpm. From each flask, 20
ml suspension was withdrawn aseptically at
intervals of 12 hours and up to 84 hours. Each
withdrawn aliquot was centrifuged at 10,000 x g
for 15 minutes at 0 to 4°C in a cooling centrifuge
and the supernatant was analyzed for xylanase
activity.
Results and Discussion
Screening of the bacteria: A xylanase producing
bacteria was isolated from the soil mixed with
petroleum products. The xylanase production by
the bacteria was screened by congo red dye
staining method (16). Xylanase activity was taken
as positive in the bacteria by the presence of clear
zone surrounding the colony (Fig. 1).These zones
were enhanced on treatment of the plate with 1
mM sodium chloride.
Morphological, biochemical and physiological
properties of the bacteria: The Gram
staining showed it to be Gram positive bacteria.
192
Microbial Type Culture Collection and Gene
Bank, Institute of Microbial Technology,
Chandigarh identified it as Paenibacillus
macquariensis and gave it Accession number
RC1819. The biochemical and physiological
properties of the bacteria are shown in Table 1.
The Paenibacillus macquariensis was grown at
various temperatures ranging from 10 o C to 42 o C
(Table 1). It showed optimum growth at 37 o C.
The growth was much poor at 42 o C.
Effect of pH on the growth of the bacteria
was observed in the pH range of 5.2 to 10.0. It
was found to have good growth at all the pHs
tested in the range of pH 5.2 to pH 10.0 (Table
1). These results showed that this bacteria has
much tolerance of pH change and has growth in
acidic to highly alkaline range.
The effect of sodium chloride on the growth
of the bacteria was also checked in the range of
2 to 10% sodium chloride and was observed to
exhibit same amount of growth in the presence
of various concentrations of sodium chloride
(Table 1). These results showed that the bacteria
also has tolerance against salinity.
The bacteria is capable of hydrolyzing
starch and casein. It also liquefied gelatin.
However, the bacteria could not utilize citrate
Fig. 1. Screening of xylanase activity by using 0.5%
Congo red dye method.
Optimization of Xylanase Secretion from Paenibacillus macquariensis