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Файл:Биотехнология = Biotechnology. Учебное пособие по английскому языку
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Let's start with the bromine. It's just alphabetically in front so this would
be one bromo-two chloro-benzene. Now it gets a little bit more involved the
IUPAC which we know is kind of the group that named most things. They tend
to everything else we've seen. So far they came up with a separate naming
mechanism from the common names but benzene it's so ingrained in the organic
chemistry computing community that all of the benzene or benzene derivative
molecules they just kind of said: “3) …”. So here's a couple of common benzene derivatives so if you have this molecule right here, if you have this molecule right here, I would actually draw the PI electrons as a circle. Actually, I'll
draw it with the double bonds. So let's say you have this molecule right here
and over here you have noh8 right there this is called a phenol. This is called
a phenol, so it's not called benzene anymore and if you had a molecule that look
like this, just like a phenol, so it's essentially it is a phenol. 4)…, that's making
this a phenol. So you start numbering there. One and then you get to the two. So
this is two bromophenol and unfortunately this is one of those things you just
kind of have to memorize. That a phenol is really just a benzene ring with an
OH group. Another one that is probably a good idea to memorize. I mean 5) … .
So it's I guess a good idea to understand as many names as possible. So if you
just have a benzene ring and then you just have a methyl group attached to that
benzene ring this is called toluene. And once again if you had a fluorine right
over there this would be one, two, three, four O2 toluene. Now a couple of other ones that you will see and once again as you know if you watched many
Khan Academy videos, I hate memorizing things, but these are just names and
these aren't systematically derived. 6) … . So it is one of those things you kind
of have to memorize. So if you have a benzene ring where the functional group,
that's kind of defining the benzene ring, it's essentially becoming a mean. We
haven't actually covered videos on means yet, and I'll do that in a future video
but it's essentially, it's replaced one of the hydrogen's in ammonia. Ammonia
has three hydrogens and one lone pair here we've replaced one of the hydrogens. Actually, there's two hydrogens here we've replaced one of the hydrogens
with a benzene ring. This type of thing you call it aniline. If I put a fluoro here,
this would be two fluoro and allene. So you use whatever the base molecule is
and then you just name it really the way we've named a lot of things before and
I'll just introduce you to two more.
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So we have a benzene ring and then you have a carboxyl group and we'll
talk more about carboxyl groups in the future but it creates carboxylic acid this
thing right here, this hydrogen it can actually be released quite easily and we'll
talk about that in the future this right here is called benzoic acid. Benzoic acid
and this name, there is a little bit more logic to this. You have the bends part for
the benzene. So let me make this in different colors. 7) … . So this actually has
some logical naming to it. Now the last one I'll introduce you to is very similar
to this. Here we just have a hydrogen and it would be an aldehyde. So let me
draw that and you could almost imagine what that's going to be called. It's benzaldehyde. You have your benzene ring and then instead of this carboxyl group
you have an aldehyde group. There's implicitly a carbon here.
Let me make that just in case it's the first time you're seeing it. You have a
carbon instead of an OH group. You have just a hydrogen. And so once again
you have a benzene. It actually makes sense to put the bends over there and
then you have the aldehyde group and then you have an aldehyde group right
over here. 8) … . Aldehyde and we'll study a means and aldehydes and carboxylic acids in much more detail in future videos and actually see reactions that
involve them. But I just wanted to expose you to this and when you see these
kinds of names you don't you know become intimidated.
PART C
I. Read the texts and find information about:
1) what PAHS are;
2) what biotransformation of PAHs is typically accompanied by;
3) where PAH derivatives are present;
4) what chemical properties PAH have.
POLYNUCLEAR AROMATIC HYDROCARBON DERIVATIVES
PAHs, in the current context, are organic compounds with two or more
aromatic rings in various structural configurations. PAHs constitute a large and
diverse class of organic compounds. However, derivatives such as tetralin
(1,2,3,4-tetrahydronaphthalene) and decalin (decahydronaphthalene, bicyclodecane) are not included in this group but are included in the alkane group
because of the saturated ring.
62
The biotransformation of PAHs is typically accompanied by the accumulation of neutral and acidic oxidation products. Both neutral and acidic watersoluble fractions are also formed when various mixed bacterial cultures degrade
weathered crude oil. However, most PAH derivatives occur as hybrids encompassing various structural components, such as in the PAH, benzopyrene.
Generally, an increase in the size and angularity of a PAH molecule results
in a concomitant increase in hydrophobicity and electrochemical stability.
The molecule stability and hydrophobicity of PAHs are two primary factors that
contribute to their persistence of in the environment.
PAH derivatives are present as natural constituents in fossil fuels and
(through refining) in crude oil products and can be formed during the incomplete combustion of organic material and are therefore present in relatively high
concentrations in products of fossil fuel refining. PAH derivatives that are released into the environment may originate from petroleum products such as including gasoline, diesel fuel, and fuel oil. The concentration of PAHs in crude
oil and crude oil products varies widely, depending on (1) the crude oil and (2)
the production method.
The toxic, mutagenic, and carcinogenic properties of PAHs have resulted
in some of these compounds (including naphthalene, phenanthrene, and anthracene) to be designated as priority pollutants. In addition, the solubility of PAHs
in aqueous media is very low, which affects degradation of these compounds
and can lead to biomagnification within an ecosystem.
The chemical properties, and hence the ability of PAHs to undergo biotransformation, are dependent in part upon both molecular size (i. e., the number
of aromatic rings) and the pattern of ring linkage. Ring linkage patterns (also
known as molecular topology) in PAHs may occur such that the tertiary carbon
atoms are centers of two or three interlinked rings, as in the linear katacondensed PAH anthracene or the pericondensed PAH pyrene.
Interest in the biotransformation degradation mechanisms and the mechanism by which biotransformation of PAHs can be achieved is of utmost importance because of the ubiquitous distribution of these chemicals in crude oil
and their potential effect on the environment. Evidence also suggests that in
some cases, PAH-toxicity also increases with size, up to at least four or five
63
fused benzene rings. The relationship between PAH-environmental toxicity and
increasing numbers of benzene rings is consistent with the results of various
studies correlating environmental biotransformation rates and PAH molecule
size.
The biodegradation of naphthalene (the simplest PAHs) process was
optimized with preliminary experiments in slurry aerobic microcosms. From
soil samples collected on a contaminated site, a Pseudomonas putida strain
(designated as M8), capable to degrade naphthalene was selected. Microcosms
were prepared with M8 strain by mixing noncontaminated soil and a mineral
medium. Different experimental conditions were tested varying naphthalene
concentration, soil/water ratio, and inoculum density. The disappearance of hydrocarbon, the production of carbon dioxide, and the ratio of total heterotrophic
and naphthalene-degrading bacteria were monitored at different incubation
times. The kinetic equation that best fitted the disappearance of contaminant
with time was determined. The results showed that the isolated strain enhanced
the biodegradation rate with respect to the natural biodegradation.
Of the four-ring PAHs, fluoranthene, pyrene, chrysene, and benzanthracene
have been investigated to various degrees. Fluoranthene, a PAH, containing
a five-membered ring, has been shown to be metabolized by a variety of bacteria, and pathways describing its biodegradation have been proposed. Fluoranthene has been used as a model compound in studies that have investigated
the effects of surface-active compounds on PAH biodegradation. Comparisons
of the mineralization of fluoranthene by four fluoranthene-degrading strains in
the presence of the nonionic
surfactants showed that responses differed between
strains. In addition, the biotransformation of pyrene,
64
a pericondensed PAH, as
well as the benzo(a) pyrene,
has been reported and several
proposed mechanistic pathways have been suggested.
Generally, aromatic constituents with five or more rings are not easily attacked and may persist in the environment for long periods. High-molecularweight aromatics comprise 2–10 % w/w conventional (light) petroleum and up
to 35 % w/w of the more viscous petroleum. But, currently, there is still a limited
information regarding the bacterial biotransformation of PAHs-derivatives with
five or more rings. Most studies have focused on the five-ring benzo(a)pyrene
due to the potential hazards of this chemical to human.
Measuring the success of the biotransformation of petroleum-related PAH
derivatives is based on several parameters. Though the lower n-alkanes are
generally considered the most biodegradable compound class within crude oils,
other studies point to exceptional conditions in which PAH derivatives degrade
preferentially to n-alkanes.
An increase in the understanding of the biotransformation of PAHdegrading microbes and the mechanisms by which PAH biotransformation occur will prove helpful for predicting the behavior of these compounds leading to
the development of practical PAH biotransformation strategies in the future.
James G. Speight, Nour Shafik El-Gendy, 2018, p. 82–85
II. Translate the following words and word combinations into Russian:
acidic oxidation products, angularity, fossil fuels, combustion of organic
material, carcinogenic properties, ring linkage, ubiquitous distribution, slurry
aerobic microcosms, isolated strain, nonionic surfactants.
III. Are the statements true or false?
1. The biotransformation of PAHs is typically accompanied by the accu-
mulation of neutral and acidic oxidation products.
2. Only acidic water-soluble fractions are also formed when various mixed
bacterial cultures degrade weathered crude oil.
3. Generally, an increase in the size and angularity of a PAH molecule re-
sults in a concomitant decrease in hydrophobicity and electrochemical stability.
4. Comparisons of the mineralization of fluoranthene by four fluoranthene-
degrading strains in the presence of the nonionic surfactants showed that responses differed between strains.
65
5. Aromatic constituents with five or more rings are easily attacked and
Title
Abstract
Key words
A. Assessment of a
novel alder biorefinery concept to meet
demands of economic
feasibility, energy
production and longterm environmental
sustainability
1. This paper describes the poten-
tial for algal biomass production in
conjunction with wastewater treatment and power generation within
a fully biotic Microbial Fuel Cell
(MFC). The anaerobic biofilm in
the anodic half-cell is generating
current, whereas the phototrophic
biofilm on the cathode is providing
the oxygen for the Oxygen Reduction Reaction (ORR) and forming
biomass. The MFC is producing
electricity with simultaneous biomass regeneration in the cathodic
half-cell, which is dependent on the
nutrient value of the anodic feedstock. Growth of algal biomass in
the cathode was monitored, assessed and compared against the
MFC power production (charge
transfer), during this process. MFC
generation of electricity activated
the cation crossover for the formation of biomass, which has been
а) hydrothermal
gasification;
supercritical
water;
methane production;
fermentation
residue;
coke formation;
sulfur removal
may persist in the environment for long periods.
6. Most studies have focused on the five-ring benzo(a)pyrene due to the
potential hazards of this chemical to human.
7. An increase in the understanding of the biotransformation of PAH-
degrading microbes and the mechanisms by which PAH biotransformation occur will fail to predict the behavior of these compounds.
IV. Match the abstracts with the papers' titles and key words.
66
Title
Abstract
Key words
harvested and reused as energy
source in a closed loop system. It
can be concluded that the nutrient
reclamation and assimilation into
new biomass increases the energy
efficiency. This work is presenting
a simple and self-sustainable MFC
operation with minimal dependency on chemicals and an energy
generation system utilizing waste
products and maximizing energy
turnover through an additional biomass recovery.
B. Hydrothermal ca-
talytic gasification of
fermentation residues
from a biogas plant
2. Aromatic chemicals that contain
an unsaturated ring with alternating
double and single bonds find numerous applications in a wide range
of industries, e. g. paper and dye
manufacture, as fuel additives, electrical insulation, resins, pharmaceuticals, agrochemicals, in food, feed
and cosmetics. Their chemical production is based on petroleum
(BTX; benzene, toluene, and xylene), but they can also be obtained
from plants by extraction. Due to
petroleum depletion, health compliance, or environmental issues
such as global warming, the biotechnological production of aromatics from renewable biomass came
more and more into focus. Lignin,
b) alnus spp.;
biorefinery
development;
alder productivity;
renewable
energy;
sustainability
assessment
67
Title
Abstract
Key words
a complex polymeric aromatic molecule itself, is a natural source of
aromatic compounds. Many microorganisms are able to catabolize
a plethora of aromatic compounds
and interception of these pathways
may lead to the biotechnological
production of value-added aromatic
compounds which will be discussed
for Corynebacterium glutamicum.
Biosynthesis of aromatic amino acids not only gives rise to l-tryptophan, L-tyrosine and l-phenylalanine, but also to aromatic intermediates such as dehydroshikimate or
chorismate from which value-added
aromatic compounds can be derived. In this review, we will summarize recent strategies for the biotechnological production of aromatic and related compounds from
renewable biomass by Escherichia
coli, Pseudomonas putida, C. glutamicum and Sac-charomyces cerevisiae. In particular, we will focus
on metabolic engineering of the extended shikimate pathway.
C. Self-sustainable
electricity production
from algae grown in
a microbial fuel cell
system
3. Biogas plants, increasing in
number, produce a stream of fermentation residue with high organic
content, providing an energy source
which is by now mostly unused. We
c) aromatic compound;
shikimate pathway;
renewables;
68
Title
Abstract
Key words
tested this biomass as a potential
feedstock for catalytic gasification
in supercritical water (T ≥ 374 °C,
p ≥ 22 MPa) for methane produc-
tion using a batch reactor system.
The coke formation tendency during
the heat-up phase was evaluated as
well as the cleavage of biomassbound sulfur with respect to its removal from the process as a salt.
We found that sulfur is not sufficiently released from the biomass
during heating up to a temperature
of 410 °C. Addition of alkali salts
improved the liquefaction of fermentation residues with a low content of minerals, probably by
buffering the pH. We found a deactivation of the carbon-supported ruthenium catalyst at low catalyst-tobiomass loadings, which we attribute to sulfur poisoning and fouling
in accordance with the composition
of the fermentation residue. A temperature of 400 °C was found to
maximize the methane yield. A residence time dependent biomass to
catalyst ratio of 0.45 g g−1 h−1 was
found to result in nearly full conversion with the Ru/C catalyst. A
Ru/ZrO2 catalyst, tested under
similar conditions, was less active.
biomass;
metabolic engineering
69
Title
Abstract
Key words
D. Biotechnological
production of aromatic compounds of
the extended shikimate pathway from
renewable biomass
4. A biorefinery concept based on
alder tree plantations on degenerated
soil is developed to comply with
indicators of economic feasibility,
fossil fuel depletion concerns, and
long-term sustainability issues. The
potential performance of feedstock
and biorefinery has been assessed
through a literature study and by
using a method developed during
the study for first hand assessment
and comparison of biorefinery system characteristics.
The management of an average alder plantation in a 6-year coppicing
system was found to fixate atmospheric nitrogen to the soil in yearly
rates between 50 and 200 kg ha−1
and produce a 6-year total dry bio-
mass quantity around 33 Mg ha−1
plus yearly leaf production. This
production could facilitate a biorefinery to serve society with production of energy related and valueadded products to substitute the use
of fossil fuels while at the same
time replenishing degenerated soils.
Integrating a biomass handling system, an LT-CFB gasifier, a diarylheptanoids production chain, an
anaerobic digestion facility, a slow
pyrolysis unit, gas upgrading and
d) photosynthetic
cathode;
microbial fuel
cell;
biomass;
photo-reactor;
algae
70
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