Volume 8(5): 382-389 (2016) - 382
J Microb Biochem Technol
ISSN: 1948-5948 JMBT, an open access journal
Ahmed et al., J Microb Biochem Technol 2016, 8:5
DOI: 10.4172/1948-5948.1000313
Research Article Open Access
Journal of
Microbial & Biochemical Technology
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ISSN: 1948-5948
Process Optimization of L-Glutaminase Production; a Tumour Inhibitor
from Marine Endophytic Isolate Aspergillus sp. ALAA-2000
Mervat Morsy Abbas Ahmed
1,2
*, Taher M Taha
3,4
, Nageh F Abo-Dahab
3
and Fareed SM Hassan
3
1
Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University (KAU), Saudi Arabia
2
Chemistry of Natural and Microbial Products Department, National Research Centre, Dokki, Giza, Egypt
3
Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Assuit, Egypt
4
Biology Department, Faculty of Science and Arts, Al Baha University, Saudi Arabia
*Corresponding author: Mervat Morsy Abbas Ahmed, Department of Biological
Sciences, Faculty of Sciences, King Abdulaziz University (KAU), Saudi Arabia, Tel:
0000-0002-0680-3205; E-mail: m_morsy_70@yahoo.com
Received July 03, 2016; Accepted July 29, 2016; Published August 09, 2016
Citation: Ahmed MMA, Taha TM, Abo-Dahab NF, Hassan FSM (2016) Process
Optimization of L-Glutaminase Production; a Tumour Inhibitor from Marine
Endophytic Isolate Aspergillus sp. ALAA-2000. J Microb Biochem Technol 8: 382-
389. doi: 10.4172/1948-5948.1000313
Copyright: © 2016 Abd-El-Karem Y, et al. This is an open-access article
distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided
the original author and source are credited.
Keywords: L-glutaminase; Marine endophytic Aspergillus sp.;
Fermentation; Optimization; Purifcation
Introduction
L-Glutaminase (L-glutamine amidohydrolase E.C 3.5.1.2) catalyses
the hydrolysis of L-glutamine to glutamic acid and ammonia. In recent
years, glutaminase has gained much attention due to their potential
applications in pharmaceuticals as an anti-leukemic agent [1,2],
favor enhancing agent [3] and an efcient anti-retroviral agent [4].
Another most promising application of glutaminase is in biosensors
for monitoring glutamine levels in mammalian and hybridoma cell
cultures without the need of separate measurement of glutamic acid
[5]. L-Glutaminase is widely distributed in animal tissues, plants and in
a variety of microorganisms including bacteria, fungi and yeast [6-8] of
which the most potent producers are fungi [9]. On an industrial scale,
glutaminases are produced mainly by Aspergillus and Trichoderma
[10-13]. Te marine endophytic microfora in the coming decades will
be the nature's best source of chemicals. Natural products metabolized
from endophytic microorganisms represent desirable sources for
efective therapeutic enzymes [8,14,15]. Marine fungi are rich profle
of biologically active metabolites, especially from genera Penicillium,
Aspergillus and Fusarium have been used aiming the development of
novel therapies for treating cancer. Whereas the marine fungi are least
studied than terrestrial counterparts and other ecological group, they
have to study due to their production of new metabolites which are not
found in terrestrial fungi [16].
Diferent methods of fermentation technology can be applied for the
production of L-glutaminase. Commercial production of L-glutaminase
had been carried out using submerged fermentation (SmF) technique
[17,18]. But nowadays, solid state fermentation (SSF) has been emerged
as a promising technology for the development of several bioprocesses
and products including the production of therapeutic enzymes on a
large-scale [19]. Te primary advantage of SSF is the fact that many
metabolites are produced at higher concentration.
Abstract
L-Glutaminases have received signifcant attention recently owing to their potential applications. All endophytic
fungi recovered from the marine soft sponge Aplysina fstularis were able to produce L-glutaminase. During
screening program, Aspergillus sp. ALAA-2000 showed the highest L-glutaminase production levels. The production
of L-glutaminase by Aspergillus sp. ALAA-2000 was evaluated under different fermentation modes and parameters.
The L-glutaminase synthesis was increased their yield after the optimization of fermentation parameters. The hot
water 40°C was the best leaching agent extracted of soy bean for L-glutaminase production (21.89 U/ml) under solid
state fermentation (SSF). The highest L-glutaminase activity (91.92 U/ml) was achieved after two days incubation
period under submerged fermentation (SmF). L-glutamine, dextrose, cysteine and Magnesium chloride supported
the highest L-glutaminase production by Aspergillus sp. ALAA-2000 under SmF at pH 4 and 27°C. Single peak of
L-glutaminase was obtained from the culture supernatant of Aspergillus sp. ALAA-2000 through ammonium sulfate
precipitation and DEAE-cellulose column chromatographyrefer to the mono meric nature of L-glutaminase enzyme.
The parameters of purifed L-glutaminase were optimized as follow: pH 10, stable at 40°C to 50°C, reaction time
30 min and substrate concentration 4.38 mg/ml. Whereas the maximum activator cation is Na
+
and different EDTA
concentrations have no effect on L-glutaminase activity which means that L-glutaminase enzymes was represent as
a non-metallic enzyme.
Tus the present study, focuses on the L-glutaminase production
as potent anticancer agents from a potential of culturable marine
endophytic isolate Aspergillus sp. ALAA-2000 isolated from the internal
healthy tissue of marine invertebrates as well as develop an economically
viable bioprocess for production of L-glutaminase by evaluating and
optimizing process parameters through manipulating the nutritional
and physical parameters using low cost substrates.
Materials and Methods
Microorganism and culture maintenance conditions
Eighteen fungal isolates used in this study were isolated from
Egyptian marine sponge Aplysina fstularis, a rich source of endophytic
microorganisms on the isolation media peptone yeast extract glucose
agar, potato dextrose agar and malt agar [20]. Te fungal cultures were
purifed, maintained at 4°C until use and examined for the production
of L-glutaminase enzyme.
Screening of fungal isolates for L-glutaminase productivity
Screening of fungal isolates for L-glutaminase activity was
performed using the modifed Czapek Dox medium (glucose 2 g,