Download Marine Microbial Enzymes: Biotechnological and Biomedical Aspects

Marine Microbial Enzymes:
Biotechnological & Biomedical Aspects
Presented by
Akram Najafi
Introduction:
• With the development of science, enzymes became inevitable for a range of
industrial processes.
• Enzymes play a key role in “green” industrial processes – they are
renewable, biodegradable, eco-friendly, and nonhazardous for a worker’s
health.
Currently, enzymes are largely used in :
• food processing industry
• detergent industry
• pharmaceutical industry
• organic synthesis
• biotechnology
• biofuels
• biomedicine
• Although many important enzymes have been isolated from plants and animals.
problems:
• large-scale cultivation
• disruption of ecosystem
• depletion of resources
Microbial enzymes:
• diverse biochemical properties
• easy genetic manipulation
• large-scale production
• Marine ecosystem: hot and cold streams, acidic and alkaline water flow, bright
surface, dark deep sea with high barometric pressure, hypersaline hydrothermal
vents, or cold seeps enriched with different minerals/gases and deep sea
volcanoes.
• This complex environment contains extremely diverse microbial populations,
including several extremophiles that can survive in and even may require
extreme physicochemical conditions that are detrimental to most living systems
on Earth.
Marine microorganisms have excellently adapted to diverse environmental
parameters:
• high salt concentration
• extreme temperatures
• acidic and alkaline pH
• extreme barometric pressure
• low nutrient availability
• Marine microbial enzymes are of special interest due to their better stability,
activity, and tolerance to extreme conditions that most of the other proteins
cannot withstand.
• So far archaea, extremophiles, and symbiotic microorganisms are reported to be
sources of most of the interesting marine enzymes with distinct structure, novel
chemical properties, and biocatalytic activity.
Detergent Industry
• Enzymes are being used in the detergent industry since 1913 and the first
bacterial protease containing detergent was available in 1956.
• Most important enzymes in this industry:
proteases, lipases, cellulase and amylase
• Ideal enzymes for detergent application:
- broad substrate specificity
- activity over a broad range of temperatures and pH
- compatible with other ingredients of detergent formulation
- active in the presence of organic solvents
Chemical and Pharmaceutical Synthesis
• Marine enzymes are of special interest for their unique catalytic properties, novel
stereochemical properties, and solvent stability.
• Marine enzymes are reported to produce pure racemic compounds that are not
observed in normal catalysis. Several examples are found in the class of lipase,
esterase, and oxidoreductase.
• Lipase B from Candida antarctica is a commercial enzyme with high
enantioselectivity and is used in enzymatic acylation of Nelarabin for the
production of its 5’-monoacetate derivative, which is an antileukemic agent
with higher solubility and thus with better bioavailability.
C. antarctica lipase B is active in the presence of organic solvents that facilitate
their use in catalyzing transesterification reactions. It is being studied for its
potential application for enzymatic synthesis of vitamin E acetate by
lipasecatalyzed transesterification
Biotechnological Research
• Enzymes are well-known tools of biotechnological research.
• Two thermostable DNA polymerases from marine microorganisms:
• - Thermococcus litoralis (Vent polymerase, New England Biolab)
- Pyrococcus furiosus (Pfu polymerase, Stratagene)
• DNA ligase from the marine isolate Thermus thermophilus is another
important enzyme in biotechnological research.
• Several restriction endonuclease, including:
AspMD1, DmaI, DpaI, AgeI, HjaI, Hac1, Hsa1, and Hag1, were isolated from
marine bacteria and some of them are already commercially available.
Biomedical Aspects
• Enzymes can be used as therapeutic agents in treating a range of physiological
disorders starting from digestive problem to neoplastic disorders.
• High affinity and specificity of each enzyme to a particular substrate is the major
advantage for their therapeutic applications.
• Stability at acidic pH of gastrointestinal tract is the biggest challenge for an
enzyme to qualify for digestive applications.
• Many plant and animal enzymes were classically used as digestive
enzymes without any remarkable tolerance to acidic pH.
• Now partially replaced by microbial enzymes and recombinant
proteins.
• Acid-stable marine microbial enzymes can be a good replacement
for these traditional digestive enzymes.
• Collagenases have medical applications in wound healing. They are effective for
the removal of dead tissue from wounds, burns, and ulcers, which can speed up
the growth of new tissues and skin grafts.
• Collagenase also has the ability to inhibit the growth of some contaminant
pathogens and is used in combination with some antimicrobial agents.
• Two amino acid hydrolyzing enzymes – asparaginase and glutaminase – have
potential application as anticancer agents.
• There is growing interest in screening of these enzymes for their exploitation as
anticancer drugs.
• Pseudomonas fluorescens is a marine bacterium that produces a salt-tolerant
Lglutaminase reported to have antineoplastic activity.
• Marine microorganisms are well-known sources of these two enzymes.
• RNA is the sole genetic material in several
pathogenic viruses, which can be killed by
ribonuclease enzymes.
• Several ribonucleases are being studied for their
potential application in treatment of HIV and
other viral infections, but mostly from higher
organisms.
• Microbial ribonucleases can be studied, and
screening of marine microorganisms may open a
potential field of antiviral research.
Biomedical applications of enzymes are being restricted by several factors:
• First, enzymes are too large to be distributed within the cells and that is why the
enzyme therapy cannot be used to treat any disease at genetic level.
• Second, in most cases, enzymes are foreign proteins to the human body and are
susceptible to antigenic reactions that may cause mild allergic reactions to severe
life-threatening immune responses.
• Third, enzymes have very short effective lifetime in blood circulation that may not
be enough to complete the enzymatic reactions to treat some disorders.
Entrapment of enzymes in nonproteinaceous materials may help in most cases, but
many of these materials often cause undesired side effects.
Bioremediation and Biofouling
• Bioremediation is the technique for removal of pollutants by biological means,
mainly by the use of microorganisms.
• Marine microorganisms have added advantages of adaptability to high salinity,
high temperatures, and extreme pH.
• Although almost all large-scale bioremediation techniques deal with intact
microorganisms, several enzymes were tested for this purpose.
• However, large-scale production and immobilization of enzymes may not be
feasible for bioremediation applications.
• Biofouling is attachment and growth of marine biomasses on submerged
surfaces.
• It increases surface roughness, damage surface coating, and enhance corrosion
of surface materials.
• Historically, biofouling is controlled by the use of antifouling coatings on
submerged surfaces that prevent microbial attachment by releasing biocides,
which are toxic to marine wildlife and hazardous to marine environment.
• Extracellular polymeric matrixes reported to play key role in biofouling. These
matrixes are composed of polysaccharides, proteins, glycoproteins, and
phospholipids– hydrolytic enzymes can potentially prevent their deposition and
inhibit biofouling at the very initial step.
• They must be stable/active in highly saline marine environments and over a
broad range of pH and temperature.
• Logically, in this environment, marine microbial enzymes should perform
better over their terrestrial counterparts.
Concluding Remarks and Perspectives
• Hundreds of marine microbial enzymes are already reported, but most reports
are concluded with bioprospecting and physicochemical characterization of the
isolated enzymes.
• A few of them are further studied for cloning and gene overexpression,
laboratory-scale product optimization, and structural profile.
• Enzyme immobilization is a very important technique for repeated catalysis in
industrial processes. It is inevitable in terms of cost- effectiveness of industrial
biocatalysis, but it is rarely practiced in marine biotechnology.
• Future research need to focus on protein engineering, structural profile, and
scale-up and downstream processing of marine microbial enzymes.
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