There are different types of culture media used for growing bacteria, categorized based on consistency and chemical composition. Solid media like agar allows separation and identification of colonies. Liquid media is used for profuse growth but mixed organisms cannot be separated. Media can also be categorized based on their chemical makeup - synthetic, basal, enriched, selective, indicator, transport, and storage media which are used for different purposes like growth, transport, or long-term storage of bacteria. Microorganisms play important roles in food production through fermentation of products like cheese, alcoholic beverages, and dairy. They are also used industrially for production of chemicals, enzymes, vitamins, and pharmaceuticals through fermentation processes.
3. TYPES OF CULTURE MEDIA FOR GROWTH OF
BACTERIA
On chemical composition
On consistency
Media are of different types:-
4. ON CONSISTENCY
1. SOLID MEDIA
Advantages of solid media:
a) Bacteria may be identified by studying the colony character
b) Mixed bacteria can be separated.
• Solid media is used for the isolation of bacteria as pure culture.
• Agar' is most commonly used to prepare solid media
• Agar is polysaccharide extract obtained from seaweed.
5. ON CENSISTENCY
Agar is an ideal solidifying agent as it is :
a) Bacteriologically inert, i.e. no influence on bacterial growth.
b) It remains solid at 37°C
c) It is transparent.
2. LIQUID MEDIA
• It is used for profuse growth, e.g. blood culture in liquid media
• Mixed organisms cannot be separated.
6.
7. ON CHEMICAL COMPOSITION
1. SYNTHETIC MEDIA:
• These are chemically defined media prepared from pure chemical substances.
• It Is used in research work.
2. Routine Laboratory Media:
It has six types
i. Basal media
ii. Enriched media
iii. Selective media
iv. Indicator media
v. Transport media
vi. Storage media
8. On chemical composition
1. BASAL MEDIA:
• Basal media are those that may be used for growth (culture) of bacteria that do
not need enrichment of the media.
• Example:
• Nutrient broth, nutrient agar and peptone water.
• Staphylococcus and Enterobacteriaceae grow in these media.
2. ENRICHED MEDIA:
• The media are enriched usually by adding blood, serum or egg.
• Example:
Enriched media are blood agar and Lowenstein-Jensen media.
• Streptococci grow in blood agar media.
9. On chemical composition
3. Selective media:
• These media favor the growth of a particular bacterium by inhibiting the growth of
undesired bacteria and allowing growth of desirable bacteria.
• Example:
• MacConkey agar, Lowenstein-Jensen media, tellurite media (Tellurite inhibits the
growth of most of the throat organisms except diphtheria bacilli)
• Antibiotic may be added to a medium for inhibition.
10. On chemical composition
4. INDICATOR (DIFFERENTIAL) MEDIA:
• An indicator is included in the medium.
• A particular organism causes change in the indicator, e.g. blood, neutral red, tellurite.
Example:
Blood agar and MacConkey agar are indicator media.
5. Transport media:
• These media are used when specie-men cannot be cultured soon after collection.
Examples:
Cary-Blair medium, Amies medium, Stuart medium.
11. On chemical composition
6. STORAGE MEDIA:
• Media used for storing the bacteria for a long period of time.
• Examples:
• Egg saline medium, chalk cooked meat broth.
12.
13. Food Microbiology
Food microbiology is the
study of the microorganisms
that inhabit, create, or
contaminate food, including
the study of microorganisms
causing food spoilage
14. Food and Diseases
• Food products are may be reason behind disease outbreaks through municipal
water supplies.
• Scientists are trying to minimize these effects by inspecting dairies and
restaurants.
• Hazard Analysis and Critical Control Point (HACCP).
• Safeguarding food from “farm to fork”
• Identifying areas where food get contaminated by harmful microbes.
• Government is sampling food to identify contaminated food.
15. Industrial Food Caning
• Food can be preserved by heating properly the container.
• But right amount of heat is required.
• So that we can avoid degradation of food appearance.
• Industrially sterilization carried by steam under pressure in a large retort.
16. Spoilage of Canned Food
• If food is incubated in high temperature, thermophilic bacteria can germinate and
grow.
• Cans usually swells from gas, and pH of food changes and sour odor produces.
• Clostridium botulinum
• Geobacillus stereothermophilic cause spoilage in canned food by only changing pH
of food.
• Mesophilic bacteria spoil food if food is underprocessed or if cans leak.
• Presence of non-endospore forming bacteria strongly suggests that can leak and
produce odor of putrefaction.
• Byssochlamys fulva cause problems in acidic foods as they are heat resistant and
acid tolerant.
17.
18. Aseptic Packaging
• Packages are made up of material that
cannot tolerate heat treatment.
• Sterilized by solution of hydrogen per
oxide and UV light.
• Metal containers sterilized by high-
temperature or superheated steam.
• High electron can also be used to
sterilize the packaging.
• Specially used for liquid food.
19. Radiation and Pressure Food Preservation
• Irradiation are lethal to microorganisms.
• The ionization irradiation is usually X-rays or gamma rays produced by
radioactive cobalt-60.
• These sources inactivate the target organisms and do not induce radioactivity in
food or packaging materials.
• Prewrapped foods such as fruits, meats and precooked chicken strips are
submerged into tanks of pressurized water.
• The pressure can reach 87,000psi this process kills many bacteria it also kills
nonpathogenic microorganisms
• This method has advantage of preserving colors and tastes of foods better than
many other methods.
20.
21. The Role of Microorganisms in Food production
Cheese
Kefir and Kumis
Alcoholic Beverages
22. Cheese
• All cheese require formation of curd.
• Curd is made up of a protein, casein and is usually formed by action of enzyme,
rennin aided by certain acidic conditions provided by lactic acid.
• Lactic acid and bacteria provide characteristic flavors and aromas of fermented
dairy products.
• Cheese are usually classified by hardness.
Romano and
Parmesan
Cheddar and Swiss Limburger and Blue Camembert
Very hard Hard Semisoft Soft
23.
24. Other Dairy Products
• Butter is made by churning cream until the fatty globules of butter separate from
liquid butter.
• Typical aroma is because of diacetyls , combination of two acetic acid molecules
which is metabolic end product of fermentation by some lactic acid.
25. Kefir and Kumis
Kefir and kumis are
fermented milk beverages that
are popular in eastern
Europe. The usual lactic acid
producing bacteria are
supplemented with a lactose
fermenting yeast to give these
drinks an alcohol content of 1-
2%
26. Alcoholic Beverages and Vinegar
• Microorganisms are involved in production of almost all alcoholic beverages.
• Beer and ale are products of grain starches fermented by yeast.
• Beer is fermented slowly with yeast strains.
• Ale is fermented relatively rapidly at higher temperature, with yeast strains.
• As yeast cannot use starch directly from grain so starch must be converted to
glucose and maltose which the yeast can ferment into ethanol and CO2 this is
known as malting and product is called as malt.
• For distilled spirits such as whisky, vodka and rum carbohydrates from cereals
grains, potatoes and molasses are fermented to alcohol.
27.
28. INDUSTRIAL FERMENTATION
It is a large scale cultivation of microbes or other single cells to produce a commercially valuable substance.
Uses
• used in the dairy, brewing, and winemaking industries other industrial products,
such as insulin and human growth hormone,
• in biotechnology to obtain useful products from genetically modified plant and
animal cells
• Vessels for industrial fermentation are called bioreactors;
• most widely used bioreactors are of the continuously stirred type which control
aeration, pH, and temperature.
• Primary metabolites such as ethanol are formed as the cells
• Secondary metabolites such as penicillin are produced during
• the stationary phase (Idiophase).
Mutant strains that produce a desired product can be selected
30. Immobilized Enzymes and Microorganisms
• Enzymes or whole cells can be bound to solid spheres or fibers . When substrate
passes over the surface, enzymatic reactions change the substrate to the desired
product.
• They are used to make paper, textiles, and are environmentally safe.
31. INDUSTRIAL PRODUCTS
AMINO ACIDS
• Glutamic acid (L-glutamate), used to make the flavor enhancer monosodium
glutamate,
• Lysine and methionine, are present only at low levels in the normal diet.
Therefore, the commercial synthesis of lysine and some of the other essential
amino acids as cereal food supplements is an important industry.
• Phellylalanine and aspartic acid (L-aspartate), have become important as
ingredients in the sugar-free sweetener aspartame (NutraSweet).
32. Industrial Products
Citric Acid
• Commonly present in oranges and lemons, now
citric acid was identified as a product of mold
metabolism .
• It gives tartness and flavor to foods. It is an
antioxidant and pH adjuster in many foods, and in
dairy products it often serves as an emulsifier
33. Industrial Products
Enzymes
• Used in the production of syrups, paper sizing and in the production of
glucose
• It is the basis of soybean fermentations
• Renin for curds in milk, proteolytic enzymes are used as meat tenderizers
or in detergents
Vitamins
• Some vitamins used as food supplements arc made by microorganisms
34. PHARMACEUTICALS
• All antibiotics were originally the products of microbial metabolism.
• Vaccines are a product of industrial microbiology
• Steroids are a very important group of chemicals that include
• Cortisol, which is used as an anti-inflammatory drug,
35. Microorganisms as Industrial Products
• The metabolic activities of Thiobacilllls peroxide‘s can be used to recover uranium
and copper ores.
• Yeasts are grown for wine- and bread making;
• Rhizobium, and Bacillus are grown for agricultural use.
37. Alternate Energy Resources Using Microorganisms
• As fossil fuels are becoming more expensive we have to find renewable resources.
Some renewable resources are directly related to microorganisms. Prominent
among renewable resources is Biomass.
“Biomass is the collective organic matter produced by living organisms,
including crops, trees and municipal wastes”
• Microbes can be used for bioconversion, the process of converting into alternative
energy resources.
• Bioconversion also plays role in decreasing the amount of waste materials which
needs to be disposed of.
39. Alternate Energy Resources Using Microorganisms
• Biomass is matter usually thought of as garbage.
• Some of it is just stuff lying around -- dead trees, tree branches, yard clippings,
left-over crops, wood chips (like in the picture to the right), and bark and sawdust
from lumber mills.
• It can even include used tires and livestock manure.
• Trash, paper products that can't be recycled into other paper products, and other
household waste are normally sent to the dump.
• Trash contains some types of biomass that can be reused. Recycling biomass for
fuel and other uses cuts down on the need for "landfills" to hold garbage.
• This stuff nobody seems to want can be used to produce electricity, heat, compost
material or fuels.
• Composting material is decayed plant or food products mixed together in a
compost pile and spread to help plants grow.
41. Global Warming and Biomass
• Using biomass can help reduce global warming compared to a fossil fuel-powered
plant.
• Plants use and store carbon dioxide (CO2) when they grow.
• CO2 stored in the plant is released when the plant material is burned or decays.
• By replanting the crops, the new plants can use the CO2 produced by the burned
plants.
• Using biomass and replanting helps close the carbon dioxide cycle.
• If the crops are not replanted, then biomass can emit carbon dioxide that will
contribute toward global warming.
• It is also a renewable resource because plants to make biomass can be grown over
and over.
43. Methane
• Methane is most convenient energy resource produced by bioconversion.
• Many countries are producing useful amounts of methane from wastes.
• For example animal manure from cattle feeding lots. Bioconversion of these
manure into biomass needs much effort.
• A major problem with any scheme for large scale methane production is the need
to economically concentrate the widespread biomass material.
47. History
• Biofuels in the solid form has been in use ever since man discovered fire. Wood
was the first form of biofuel that was used even by the ancient people for cooking
and heating.
• Biofuels powered the first lamps and internal combustion engines. The shift from
biofuel to petroleum products like kerosene and gasoline as primary fuel source
took place in the 1860s, for oil lamps, and in the early 20th century, for
automotive fuels.
• In World War II, the high demand of biofuels was due to the increased use as an
alternative for imported fuel.
• Biofuels have continued to be used, straight or in blends with petroleum products,
as fuels for diesel and spark ignition engines throughout the 19th and 20th
centuries.
48. Pigeon “spirit lamp”
for alcohol –
turpentine blend,
manufactured in
France 1880s.
Kerosene parlor
lamp in the
background
49. • Nikolaos August Otto was the first to tell about the use of ethanol.
• Rudolf Diesel is the German inventor of the diesel engine. He designed his diesel engine to run in
peanut oil
• Henry Ford designed the Model T car which was produced from 1903 to 1926. This car was
completely designed to use hemp derived biofuel as fuel. Most of the vehicles like trucks and cars
began using this form of fuel which was much cheaper and efficient.
• Britain was the second country which came up with the concept of grain alcohol mixed with petrol
• The wars frames were the periods when the various major technological changes took place
50. How did biofuels come back into fashion?
• The world experienced a energy revolution during the period of 1973 & 1979
• The constant shortage of fuel attracted the attention of the various academics and
governments to the issues of energy crisis and the use of biofuels. The twentieth
century came with the attention of the people towards the use of biofuels. Some of
the main reasons for the people shifting their interest to biofuels were the rising
prices of oil, emission of the greenhouse gases and interest like rural
development.
51. Two Types of Energy Resources
Non- renewable
• Oil
• Natural gas
• coal
Renewable
• Solar energy
• Hydropower
• Biofuel
• Biomass
• Tidal energy
• Wind energy
• Nuclear energy
52. Introduction
• Biofuels are energy sources made from living things, or the waste that living things produce.
• Biofuels can come from a wide variety of sources and can be roughly divided into four
categories or "generations:“
First generation: biofuels are made from sugars, starches, oil, and animal fats that are converted into fuel
using already-known processes or technologies. These fuels include biodiesel, bioalcohols, ethanol, and
biogases, like methane captured from landfill decomposition.
Second generation: biofuels are made from non-food crops or agricultural waste, especially ligno-cellulosic
biomass like switch-grass, willow, or wood chips.
Third generation : biofuels are made from algae or other quickly growing biomass sources.
Fourth generation: biofuels are made from specially engineered plants or biomass that may have higher
energy yields or lower barriers to cellulosic breakdown or are able to be grown on non-agricultural land or
bodies of water.
53. Definition
A biofuel is defined as any fuel whose energy is obtained through a process of
biological carbon fixation. i.e. any process that converts carbon dioxide into a
molecule that would be found in a living organism is carbon fixation. If this
process occurs in a living organism, it is referred to as 'biological carbon fixation'.
• Biofuel, also called agro fuel, is fuel that is mixed with parts of biological
material. It can be made of relatively any material from ethanol, wood, vegetable
oil and even algae. It is a possible substitute for petroleum fuel for vehicles
55. • Biofuels are important for a number of reasons. Transport is dependent on finite
fossil fuels such as oil and petroleum for its energy needs so it is important that
we move towards more renewable
• It can be good for our health
• It can be good for our car engines
• To reduce reliance on foreign oil
• To lower emissions of greenhouse effect
• Energy security
58. Bioethanol
• Ethanol is an alcohol made from feed stocks (such as corn), sugar cane,
or cellulosic material. Ethanol is generally blended with gasoline for use in
internal combustion engines.
• Ethanol can be produced from biomass by the hydrolysis and sugar fermentation
processes.
59. Methods
• Concentrated Acid Hydrolysis Process
• Dilute Acid Hydrolysis
• Wet Milling Processes
• Dry Milling Process
• Sugar Fermentation Process
60. Uses of ethanol
• It is blended with petrol to make a truly sustainable transport fuel, it's used in
cosmetic and other manufacturing processes, and it creates the clean burning,
beautiful flame in our fireplaces.
61. Biomass
• The term "biomass" refers to organic matter that has stored energy through
the process of photosynthesis. It exists in one form as plants and may be
transferred through the food chain to animals' bodies and their wastes, all of
which can be converted for everyday human use through processes such as
combustion, which releases the carbon dioxide stored in the plant material. Many
of the biomass fuels used today come in the form of wood products, dried
vegetation, crop residues, and aquatic plants
• Many different kinds of biomass, such as wood chips, corn, and some types of
garbage, are used to produce electricity. biomass can be converted into liquid
fuels called biofuels that can power cars, trucks, and tractors
62.
63. Biodiesel
• It is mineral acid and chemically kown as fatty aid methyl
• Biodiesel is a renewable fuel made from seed oils (canola, sunflower, soybean,
etc.),
64. Transterfication
• It is chemical process called Transterfication whereby the glycerin is separated
from the fat or vegetable oil. The process leaves behind two products -- methyl
esters (the chemical name for biodiesel) and glycerin (a valuable byproduct
usually sold to be used in soaps and other products).
65.
66. Why use biodiesel?
• it is non toxic and renewable
• used in cars
• can be used alone/blended
• carbon neutrality
• can be made from waste restaurant oils
• high lubricity
• biodegradable
• not require modifications to a diesel engine to be used.
• reduced exhaust emissions compared to petroleum diesel fuel.
67. Algal biofuels
• Algae are primitive plants, usually aquatic, capable of synthesizing their own food
by photosynthesis. Algae is currently being investigated as a possible feedstock for
producing biodiesel !
• Different species of algae can be used fresh water or seawater algal
• Have a high lipid
• Grow rapidly
• Require warm temperature
68. Growing algae
• Raceway ponds or photo bioreactors are most common for algal based biofuels.