Biochemical processes - the engineering resource

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22 Φεβ 2013 (πριν από 4 χρόνια και 5 μήνες)

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Biochemical

Engineering
:

extension

of

chemical

engineering

principles

to

systems

using

a

biocatalyst

to

bring

about

desired

chemical

transformation
.




Mainly

deals

with

the

design

and

construction

of

unit

processes

that

involve

biological

organisms

or

molecules
.



Its applications are used in the pharmaceutical,
biotechnology, and water treatment industries





Utilizes

biological

cells

to

perform

catalytic

reactions

on

a

substrate,

called

the

media,

to

produce

one

or

more

useful

chemical

species,

called

the

product
.

The

reactor

is

often

called

a

continuous
-
stirred

tank

reactor

(CSTR),

a

fermentor
,

a

chemostat
,

or

a

turbostat
.


Additionally,

a

reactor

may

utilize

only

the

proteins

that

specifically

catalyze

desired

reactions,

called

enzymes
.

Instead

of

growing

biological

cells

and

using

them

as

'mini
-
reactors'

to

produce

the

desired

product,

one

can

extract

the

necessary

enzymes

from

the

cell

and

use

them

to

catalytically

synthesize

the

product
.


Cells are living organisms that require specific
conditions for growth,
production



Cells grow in culture medium (nutrients
)



Bioproducts are often sensitive to external
conditions (T, pH
).




Enzyme,

any

one

of

many

specialized

organic

substances,

composed

of

polymers

of

amino

acids,

that

act

as

catalysts

to

regulate

the

speed

of

the

many

chemical

reactions
.



e
.
g
;

the

metabolism

of

living

organisms,

such

as

digestion
.


Enzymes

are

large

proteins

that

speed

up

chemical

reactions
.
In

their

globular

structure,

one

or

more

polypeptide

chains

twist

and

fold,

bringing

together

a

small

number

of

amino

acids

to

form

the

active

site,

or

the

location

on

the

enzyme

where

the

substrate

binds

and

the

reaction

takes

place
.



The

enzyme

itself

is

unaffected

by

the

reaction
.



When

the

products

have

been

released,

the

enzyme

is

ready

to

bind

with

a

new

substrate
.




Metabolism

(chemistry),

inclusive

term

for

the

chemical

reactions

by

which

the

cells

of

an

organism

transform

energy,



maintain

their

identity,

and

reproduce
.



Anabolism,

or

constructive

metabolism
,

is

the

process

of

synthesis

required

for

the

growth

of

new

cells

and

the

maintenance

of

all

tissues
.



Catabolism,

or

destructive

metabolism
,

is

a

continuous

process

concerned

with

the

production

of

the

energy

required

for

all

external

and

internal

physical

activity
.


A

microorganism

or

microbe

is

an

organism

that

is

so

small

that

it

is

microscopic

(invisible

to

the

naked

eye)
.



Micro

biology

is

the

study

of

these

micro
-
organisms
.


Prokaryotes

are

unicellular


(in

rare

cases,

multicellular)

organisms

without

a

nucleus
.



The

name

prokaryote

comes

from

the



Greek

pros

meaning

before

and


karyon

meaning

referring

to

the

nucleus
.


The

difference

between

the

structure

of

prokaryotes

and

eukaryotes

is

so

great

that

it

is

considered

to

be

the

most

important

distinction

among

groups

of

organisms
.



Most

prokaryotes

are

bacteria


Prokaryotic

cells

are

small

&

simple

cells
.



They

usually

exist

alone
.



There

shape

may

be

spherical,

rod

like

or

spiral
.

Their

size

may

be

0
.
5

to

3

mm
.



They

grow

rapidly
.



They

adopt

to

environment

and

their

rapid

growth

and

biochemical

versatility

makes

it

good

choice

for

research

and

chemical

processing
.


Eukaryotes

are

organisms

with

complex

cells,

in

which

the

genetic

material

is

organized

into

membrane
-
bound

nuclei
.


The

name

comes

from

the

Greek



eus

or

true

and

karyon

referring

to

the

nucleus
.



These are 1000 to 10000 times larger than
prokaryotics
.


All cells of higher organisms belong to this family


Mostly these are plant and animal cells


These are more complex



Fermentation

is a process of chemical change caused by
organisms usually producing energy or heat.



Fermentation

typically

refers

to

the

fermentation

of

sugar

to

alcohol

using

yeast,

but

other

fermentation

processes

include

the

making

of

yogurt
.

The

science

of

fermentation

is

known

as

zymology
.


'an energy
-
generating process’


Fermentation,

a

process

in

which

microorganisms

convert

complex

organic

molecules

into

simpler

molecules,

is

used

in

the

production

of

cheese
.



Anaerobic

fermentation


Some

micro

organism

do

not

require

oxygen

and

this

type

of

fermentation

is

called

anaerobic

fermentation
.


Aerobic

fermentation


Aerobic

fermentation

require

the

use

of

substantial

amounts

of

oxygen





Yeasts

have

been

used

since

prehistoric

times

in

the

making

of

breads

and

wines,

but

their

cultivation

and

use

in

large

quantities

was

put

on

a

scientific

basis

by

the

work

of

the

French

microbiologist

Louis

Pasteur

in

the

19
th

century
.

Today

they

are

used

industrially

in

a

wide

range

of

fermentation

processes
;

medicinally,

as

a

source

of

B
-
complex

vitamins

and

as

a

stage

in

the

production

of

various

antibiotics

and

steroid

hormones
;

and

as

feed

and

foodstuffs
.



Pure yeast cultures are grown in a medium of sugars, nitrogen sources,
minerals, and water.


Culture

is

the

term

given

to

microorganisms

that

are

cultivated

in

the

lab

for

the

purpose

of

studying

them
.



Medium

is

the

term

given

to

the

combination

of

ingredients

that

will

support

the

growth

and

cultivation

of

microorganisms

by

providing

all

the

essential

nutrients

required

for

the

growth

in

order

to

cultivate

these

microorganisms

in

large

numbers

to

study

them
.

















Among

the

different

kinds

of

microorganisms

the

two

groups

that

can

be

grown

in

cultures

are

bacteria

and

fungi
.



Algae

and

protozoa

require

many

different

nutrients

in

minute

quantities

that

are

difficult

to

anticipate

and

prepare

in

the

lab
.





Primary

ingredients

required

by

all

living

organisms

include
:



a

carbon

source
,

water,

minerals,

and

a

nitrogen

source
.


The

ingredients

in

a

medium

will

affect

the

chemical

nature

of

the

medium
.

This

is

important

because

organisms

vary

in

their

requirement

for

different

environments
.






One

such

property

is
:


pH

(which

is

a

measure

of

the

amount

of

hydrogen

ions

in

a

particular

medium
)
.



This

has

to

be

monitored

during

the

preparation

of

media

since

this

will

influence

the

kind

of

organisms

that

are

able

to

grow

in

the

medium
.




The

pH

of

the

medium

will

thus

determine

which

organisms

are

able

to

grow

on

the

medium
.




For

example




fungi

prefer

acidic

media

for

their

growth

while

bacteria



grow

on

neutral

pH

media
.


The primary function of culture media is to be able to
grow
particular
organisms on/in them.
It
is important that these
media are devoid of any other living
organisms
.



This
is possible through the process of
sterilization


(
a process by which all living organisms and their spore forms
are
killed and the medium is made sterile)





Culture media are most commonly sterilized through the
process of
autoclaving

(using
high temperatures

that will kill
all living
organisms
under
increased pressure

for specified
periods of time


in
an appliance called the
autoclave
)