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Файл:Биотехнология = Biotechnology. Учебное пособие по английскому языку
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4. Now let's get back to biomass. Biomass is any organic matter of recent bio-
genic origin used to supply energy or materials. Now this can range from purpose grown crops such as short rotation coppice, and to energy grasses,
through to the biodegradable fraction of municipal waste. What all of these
materials have in common is that they contain carbon atoms that have relatively recently been sequestered from the atmosphere. When we use the material to provide energy and convert the hydrocarbon to carbon dioxide and water, we are only returning the carbon dioxide that was recently removed from
the atmosphere. It doesn't actually increase the net long-term burden of CO2
in the atmosphere. Anthropogenic climate change is caused by an accumulation of greenhouse gases in the atmosphere. If we have a net transfer of the
carbon stock sequestered by plants in the ecosphere to the atmosphere, that
would be a problem. This could for example, occur with unsustainable logging practice. So, forest derived materials are only sustainable if the forest
area is being maintained through harvest periods. However, as long as the
carbon is being cycled from ecosphere to atmosphere on a relatively short cycle time, there is no net long term increase in atmospheric GHG concentrations. However, there will be steps along the bioenergy chain where we emit
greenhouse gases.
5. But for other parameters the bioenergy system is actually less sustainable
and this commit policy making very challenging. his sort of system can also
help us to inform system improvements.
6. Bioenergy is low carbon because the carbon dioxide released when bio-
mass is converted has been sequestered from the atmosphere relatively recently when the plant grew. So releasing it is more akin to recycling CO2 and
provided that the biomass resource is sustainably managed, this doesn't increase the long term atmospheric burden of greenhouse gases.
7. For example, we might compare it to the current fossil fuel energy use.
And so these graphs that you can see here show the carbon emissions associated with using biomass in different ways. The one on the left shows that
woodchip boilers, small and large electricity plants, all give similar, very significant reductions. But if we frame things differently and instead consider the
greenhouse reductions that are achieved per unit of biomass. So that's taken
into point the efficient use of the biomass resource, we need up with quite
a different rank ordering.
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8. So we may need to think about whether biomass production is encouraging
forest clearance for land grabs. And how farm workers are treated on biofuel
plantations compared to the conditions they would experience on other land.
There are a huge number of things that could be considered. On a comprehensive, sustainability assessment really should take all of these into account.
Although depending on the resource and geographic region, some things may
be more important than others. And it may make sense to focus on some, rather than all, of the criteria that you can see here.
9. Studies by the UK government have shown that bioenergy could provide
up to 50 % of the UK's renewable energy across heat, transport fuels, and
electricity by 2020. So it is important that we think carefully about the wider
impacts and challenges of using biomass for energy.
10. Now this graph shows a semiquantitative assessment of all the criteria I
showed you on the previous slide for a particular bioenergy system. The way
to think about this is that the blue circle is the reference system, in this case
it's a fossil fuel diesel system and if we stretch that circle then that equates to
being more sustainable. And as you can see some parameters score well on
the bioenergy system that's the purplish colored one, actually a first and more
sustainable choice for parameter number 1, number 4, 11 and so on.
11. I said that we look at greenhouse gas balances along the whole supply
chain. When we do that, we use a technique which is called lifecycle assessment, and this involves looking at a product. In this case, the product is a unit
of energy. From the cradle where it is produced, in this case that's in a field
where the biomass is grown. Through its whole life cycle to its end use point
when it delivers energy to the consumer. By doing this, we can establish the
greenhouse gas impact of that unit of energy compared to a reference level.
12. We might try to redesign the bioenergy system to address some of those
most negative impacts. As we saw on that previous slide, when we implement
bioenergy, some things can be more sustainable, and some things can be less.
And really, bioenergy has potential to offer immense benefits, in terms of
greenhouse gas savings, employment creation, global trade opportunities, especially when we're looking at developing countries. But there are also risks,
risks of undesired social conditions and ecosystem impacts.
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13. Again, this shows that it is important to understand what exactly the en-
vironmental policy objective is at the outset when considering the use of biomass to encourage fire policy mechanisms. Of course, I've just been talking
about greenhouse gases and carbon, and I showed earlier the three pillars of
sustainability. When we think in that scale, we need to be thinking about an
awful lot more than just greenhouse gases. Bioenergy systems have a whole
host of ecological impacts, many of which are related to the production on
land. So, when we look at the impacts for bioenergy we need to think about
the toxicity impacts of pesticides used in plant production. The biodiversity
impacts of introducing new species. The hydrological impacts of planting
crops and forests.
14. One very clear message we get is that under a whole range of possible
future conditions, the biomass resource that we have available for use will be
dominated by waste. So, we really need to focus on better ways of using and
making the most of waste if we want a really sustainable bioenergy future.
15. Lots of people talk about using things sustainably. It all sounds very posi-
tive, but it can be difficult sometimes to know what they really mean. One definition was formalized in the Bruntland Report by the World Commission on
Environment and Development. And it said that sustainability meant meeting
the needs of the present without compromising the ability of future generations to meet their own needs. But of course, means that we need to protect
the environment. So that means preserving our fuel reserves and biodiversity,
while avoiding pollution and dangerous greenhouse gas levels, but there's
more to it than that. If we think holistically about our environment as the
place where we exist, we realize that there's also a social dimension to this
and so sustainable development should be just and equitable. For example,
not exploiting the resources of one group to provide the needs of another. In
the society we inhabit today, there is global interaction and trade. Also, necessary, sustainable activity contributes in some way to economic growth. We
cannot indefinitely continue something if it has a significant uncompensated
financial cost. So, we think of sustainable development as taking place in
a space that has constrained by environmental protection, economic growth
and social justice. We call these the three pillars of sustainability.
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16. So we need to think very carefully about how we balance those risks and
rewards when we're engineering the systems. Sustainable engineering is about
balancing these in a context appropriate way where we think about the users
on the things surrounding it. That's the end of this module session. If you
would like any further information on this topic, you will find a lot of papers
and a lot of information and links to the UK Institutes doing work on this at
the SUPERGEN Bioenergy Hub website www.supergenbioenergy.net. My
contact details, Patricia Thornley at Manchester are listed here as well. Thank
you for listening.
II. Give Russian equivalents to the following words and phrases:
sustainable, degrees centigrade, decimate, renewable energy provision, energy consumption, biogenic origin, coppice, GNG, semiquantitative, reference
level, holistically.
III. Make five special questions to the text and ask your partner. Then
change the roles.
IV. How can biotechnology benefit environmental protection, economic growth and social prosperity? Make a presentation on the topic.
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UNIT V
conventional petroleum
природная нефть
branched alkane derivatives
разветвленные алкановые производные
cycloalkanes
циклоалканы, нафтены
triterpane
тритерпан
isoprenoids
изопреноиды
Hopane
гопан
w/w (per cent weight in
weight)
весовое соотношение
benzopyrene
бензопирен
biomagnification
биоконцентрация
angularity
угол наклона
hydrophobicity
гидрофобность
kata-condensed
ката-конденсированный
ubiquitous
широко распространенный; универсальный
anthracene
антрацен
inoculum density
плотность посева (клеток в культуре)
fluoranthene
флуорантен
Chrysene
хризен
surfactants
поверхностно-активные вещества
Lignin
лигнин
Cleavage
разрыв химической связи; разрыв химиче-
ской цепи
DERIVATIVES
PART A
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I. Answer the questions:
1. What are alkanes?
2. What are the properties of branched alkane derivatives?
3. What is important from the standpoint of biotransformation?
II. Read the text and check the answers.
ALKANE DERIVATIVES
Alkanes are major constituents of conventional petroleum and petroleum
products. Conventional (light) petroleum contains 10–40 % w/w normal alkanes, but weathered and heavier oils may have only a fraction of a percent.
Higher molecular weight alkanes constitute 5–20 % w/w of light oils and up to
60 % w/w of the more viscous oils and tar sand bitumen. Of these, the normal
alkane series (straight-chain alkane series) is the most abundant and the most
quickly degraded. Compounds with chains of up to 44 carbon atoms can be metabolized by microorganisms, but those having 10–24 carbon atoms (C10–C24)
are usually the easiest to metabolize. Shorter chains (up to approximately C8)
also evaporate relatively easily. Only a few species can use Cl–C4 alkanes and
C5–C9 alkanes are degradable by some microorganisms but toxic to others.
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Branched alkane derivatives are usually more resistant to biodegradation
than normal alkanes but less resistant than cycloalkanes (naphthenes) – those
alkanes having carbon atoms in ring like central structures. Branched alkanes are
increasingly resistant to microbial attack as the number of branches increases.
At low concentrations, cycloalkanes may be degraded at moderate rates, but
some highly condensed cycloalkanes can persist for long periods after a spill.
Understanding the bacterial degradation pathway of cycloalkane derivatives, as well as that of n-alkane derivatives, is important from the standpoint of
biotransformation.
Generally, with respect to the molecular composition of the aliphatic constituents of petroleum and petroleum-related products, microbial biotransformation will biotransform the n-alkane derivatives and the branched-chain alkanes. The polycyclic alkane derivatives of the sterane and triterpane type tend
to be somewhat resistant to biotransformation. Since this is the case even for
naphthene-type petroleum (which is originally depleted in nonring alkane derivatives), the biotransformation of petroleum constituents may be restricted to
n-alkane derivatives and isoprenoid derivatives.
James G. Speight, Nour Shafik El-Gendy, 2018, pp. 80–81
III. Complete the sentences with the following words and word com-
binations:
viscous, derivatives, microorganisms, resistant, condensed, abundant.
1) Branched alkane derivatives are usually more … to biodegradation than
normal alkanes.
2) The normal alkane series (straight-chain alkane series) is the most …
and the most quickly degraded.
3) The polycyclic alkane … of the sterane and triterpane type tend to be
somewhat resistant to biotransformation.
4) Some highly … cycloalkanes can persist for long periods after a spill.
5) Higher molecular weight alkanes constitute 5–20 % w/w of light oils
and up to 60 % w/w of the more … oils and tar sand bitumen.
6) Compounds with chains of up to 44 carbon atoms can be metabolized
by … .
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IV. Match two halves of the sentence to make one.
1. Branched alkanes are increasingly re-
sistant to microbial attack
a) 5–20 % w/w of light oils
2. Alkanes are major constituents of
b) by some microorganisms but
toxic to others.
3. Understanding the bacterial degrada-
tion pathway of cycloalkane derivatives
c) n-alkane derivatives and isopre-
noid derivatives.
4. Only a few species can use Cl–C4 al-
kanes and C5–C9 alkanes are degradable
d) conventional petroleum and pe-
troleum products.
5. Higher molecular weight alkanes
constitute
e) is important from the standpoint
of biotransformation.
6. The biotransformation of petroleum
constituents may be restricted to
f) as the number of branches in-
creases.
V. Make up a summary of the text.
PART B
I. Read the texts and find information about:
1. How are aromatic hydrocarbon derivatives characterized?
2. Why is it uncommon to find organisms that could effectively react and
change both aliphatic constituents and aromatic constituents of petroleum?
AROMATIC HYDROCARBON DERIVATIVES
Aromatic hydrocarbon derivatives are characterized by the presence of at
least one benzene (or substituted benzene) ring. The low-molecular-weight
aromatic hydrocarbon derivatives are relatively easily subject to biotransformation. Light crude oil typically contains between 2 % and 20 % w/w lowboiling aromatic compound derivatives, whereas heavy oil contains less than
2 % w/w aromatic compounds. As the molecular weight and complexity increase of the aromatic derivatives increases, biotransformation is less likely to
occur. Thus, the degradation rate of PNA derivatives is slower than the degradation rate of monocyclic aromatic derivatives.
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However, it is uncommon to find organisms that could effectively react
a) Well you know what we'll just going to use the names that everyone uses …
b) … at least for me and organic chemistry the most confusing thing is when
someone says the name of a molecule that it sounds like they expect you to
understand but you don't understand it …
c) This is called a benzaldehyde or this molecule is called benzaldehyde
bends …
and change both aliphatic constituents and aromatic constituents of petroleum
possibly due to differences in metabolic routes and pathways for the degradation of the two classes of hydrocarbons. There are indications of the existence
of bacterial species with propensities for simultaneous degradation of aliphatic
hydrocarbons and aromatic hydrocarbons. This rare ability may be as a result of
long exposure of the organisms to different hydrocarbon pollutants, resulting in
genetic alteration and acquisition of the appropriate degradative genes.
The biodegradation of alkyltetralins has also been studied. However, tetralin has been shown to be biodegraded by both mixed cultures of microbes and
by some strains able to utilize the compound as sole carbon and energy source.
It has been demonstrated that rhodococci strains are able to react with alkyltetralin derivatives. The identification of such bacteria capable of the bioreactivity of alkyltetralins may be an important step toward the development of
bioremediation strategies for sites contaminated by toxic aromatic hydrocarbons.
James G. Speight, Nour Shafik El-Gendy, 2018, p. 81
II. Translate the following words and word combinations into Russian:
1) low-molecular-weight aromatic hydrocarbon derivatives; 2) molecular
weight; 3) degradation rate; 4) aliphatic constituents; 5) metabolic routes;
6) genetic alteration; 7) acquisition; 8) toxic aromatic hydrocarbons.
III. Make up five special questions to the text and ask your partner.
Then change the roles.
IV. Watch video 5 and fill in the missing sentences
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d) It's a six-carbon ring with three double bonds …
e) But let's say you have a bromine right there, what you do is you start num-
bering at the group …
f) And I just talked about this in the last video just to show that really neither
of these configurations is exactly right …
g) The benzene part that gives us the bends right there and then in general
whenever you have a carboxyl group like this, it becomes a carboxylic acid
and you tend to add the acid to the end …
h) The chemistry community just uses them because that's the way they name
them …
I mentioned in the last video that 99 % of the aromatic compounds that
you'll see in an organic chemistry class is either going to be benzene or molecule derived from benzene or a molecule derived from benzene. So what I want
to do in this video is just familiarize you with some of these molecules and how
to name them so you know what you're looking at or I guess so you could name
what you're looking at. So you've seen this multiple times benzene just looks
like this. 1) … . These three double bonds like that and that's it's not the only
configuration. Sometimes it's shown to be in resonance with this form right
here. So the double bonds all flip around the circle like that or sometimes it's
simply drawn like this. 2) …, that these PI electrons are just circular eight.
They're just moving around the entire ring and sometimes you'll just have the
hexagon with a circle on the inside to show that the PI electrons just floating
around the entire ring. Now if I were to add something to the benzene ring it's
pretty straightforward to name it. So say I have this molecule right here, this
molecule right here, let's say I have that benzene but let's say this carbon over
here, it has one, two, three bonds. If I didn't draw anything else, you just assume
that there's also a hydrogen here. But maybe there's no hydrogen there. Let me
do this in a different color. Maybe you have a chlorine there. Well this is just
chlorobenzene. If that was a bromine it would be bromobenzene. Let me change
it a little bit. Let's see how to chloro there and let's say you had a oh I don't
know let's say you had a bromo over here. Let's say you have a bromo over
there. Draw the bromo so you could just start numbering, you could actually
start numbering in either place.
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