ฉันต้องใช้ภาษาอังกฤษถูกหลักไวยากรณ์
To test the relationship between biofilm and cellulose
production, cellulose produced by different strains was
quantified according to the method of Updegraff[22].
Ten milliliters of a 24 h culture for each isolate was
dispensed into 15 mL centrifuge tube. The culture was
then centrifuged at 3 000 r/min with a centrifuge. The
supernatant was decanted after centrifugation. Three
milliliters of acetic nitric acid reagent was added in two
installments (1 mL then 2 mL) and mixed on the vortex on
each addition. The solution in the 15 mL centrifuge tubes
were covered with foil to reduce evaporation and create
reflux and then placed in boiling water bath for 30 min.
After this period of boiling the tubes were centrifuged
again for 5 min at 3 000 r/min. The supernatant was
decanted and 10 mL of H2SO4 was added in 3 installments
with intermittent mixing. The mixture was allowed to stand
for 1 h. One milliliter of mixture was then dispensed into
a test tube containing 100 mL of distilled water. This was
mixed thoroughly by agitation and 1 mL of the mixture
dispensed into 4 mL of distilled water. The mixture was
then placed in ice bath to cool. Ten milliliters anthrone
reagent was added by layering with a pipette. This was
followed subsequently by thorough mixing and placing
tube back in ice bath until all tubes were mixed. The tubes
were then capped and placed in boiling water for 16 min,
cooled on ice bath for 2-3 min and allowed to stand at room
temperature (22 °C) for 5-10 min. One milliliter of each
sample was placed in each cuvette for subsequent reading
in the spectrophotometer. The absorbance of each sample
was then read on the spectrophotometer (Springfield, UK) at
620 nm wavelength against a reagent blank[22]. Calculation
of cellulose concentration was done against cellulose
standards and reported in µg