الفهرس 
Microorganisms employed for inulinase productionOnly 14 pages are availabe for public view
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Abstract
Ahmed Sayed Ahmed El-sayed Younes: Bio-Conversion of Some
Food Processing Wastes for The Production of Economically
Valuable Products. Unpublished M.Sc. Thesis, Department of Food
Science, Faculty of Agriculture, Ain Shams University, 2017.
This study was designed to produce fructose syrup (FS) by
enzymatic hydrolysis. This enzymatic hydrolysis was carried out using
inulinase enzyme that obtained from the fermentation process of
cellulosic substrates using the yeast Kluyveromyces marxianus NRRL
Y-7571 under solid state fermentation of raw materials that store inulin
as a main carbohydrate.
Nine solid state substrates, sugarcane bagasse (100%), potato
peels (100%), artichoke leaves (100%), bagasse : potato peels
(50%:50%), bagasse : artichoke leaves (50%:50%), potato peels :
artichoke leaves (50%:50%), bagasse : potato peels: artichoke leaves
(20%:30%:50%), bagasse : potato peels : artichoke leaves
(30%:50%:20%), bagasse : potato peels : artichoke leaves
(50%:20%:30%) were tested to select the most suitable medium for
inulinase production using the yeast Kluyveromyces marxianus NRRL
Y-7571 under solid state fermentation. The best cellulosic waste ratio
was bagasse : artichoke leaves (50:50%), the inulinase activity reached
to 414.72 U/g substrate and its specific activity was 669.81 U/mg
protein.
The optimum conditions for K. marxianus NRRL Y-7571 growth
and inulinase production had been studied and were found to be as
follows: incubation period: 2 days, incubation temperature: 30°C, initial
pH in solid state medium: 6, inoculum size: 2 ml/5g waste, moisture
content of solid state medium: 60% and waste ratio of sugarcane bagasse
: artichoke leaves were 75:25 w/w. Under these conditions, it was
showing up an inulinase activity and specific activity of 1252.08 U/g
substrate and 1421.98 U/mg protein, respectively.
The produced inulinase under the obtained optimal conditions
was partially purified by ammonium sulfate using dialysis technique.
This step caused an increase in the specific activity of inulinase enzyme
to 1841.42 U/mg protein.
The optimum conditions for inulinase activity were found to be
as follows: incubation period: 30 min, incubation temperature: 55°C,
optimum pH: 4.8, substrate concentration: 0.5%, enzyme size in mixture
reaction:
150 µl and agitation speed: 100 shake. Under these conditions, it was
observed an inulinase activity and specific activity of 1835.61 U/g
substrate and 3078.68U/mg protein, respectively.
Some important industrial parameters for produced inulinase
enzyme were studied like thermal stability and pH stability, the results
referred that inulinase enzyme was stable up to 55°C and pH value range
between 4 - 6, respectively.
The obtained optimum conditions for inulinase activity were
applied to hydrolyze the inulin that extracted from jerusalem artichoke
for the production of fructose syrup to use for supplement food
manufactures process. The produced fructose syrup (FS) was applied in
biscuits manufacture, physical properties (width, thickness and spread
ratio) and sensory evaluation (color, texture, odor, taste and over
acceptability) showed that biscuits which produced without commercial
fructose syrup and replaced with 60% by the produced fructose syrup
from the water ratio in the control formula gave higher scores for
physical and sensory evaluations than other treatments and control.
It could be recommended that commercial fructose syrup could
be replaced with 60% by the produced fructose syrup under this study to
produce cheaper product and more acceptable for the customer that
achieved higher profit to food processing factories.
Key words: Sugarcane bagasse, Potato peels, Artichoke leaves,
Jerusalem artichoke, Corn steep liquor, Kluyveromyces
marxianus NRRL Y-7571, Solid state fermentation,
inulinase production, Inulin, Biscuits, Fructose syrup.