The document details the bioconversion of waste into biofuels, covering types such as ethanol, biodiesel, and biogas, and their production from various biomass sources. It emphasizes the advantages of biofuels, including being eco-friendly, cost-efficient, and reducing greenhouse gas emissions, while also addressing challenges like high production costs and potential impacts on food supply. The production processes and microbial contributions, along with key features of biofuels, are also discussed.

1. BIOCONVERSION OF WASTE
FOR FUELS
BY : ANJALI SHARMA (MSC)
DEPARTMENT OF MICROBIOLOGY

2. BICONVERSION OF WASTE FOR FUELS
(CONTENTS) :
 INTRODUCTION
 BIOMASS
 DESIRABLE FEATURES OF BIOFUELS
 ETHANOL
 BIODIESEL
 BIOGAS
 ADVANTAGES OF BIOFUELS

3. INTRODUCTION :
 BIOFUEL :are liquid or gaseous fuels derived from the living things , or from the
fermenting biomass and the waste they produce.
 Microbial fuel produced can contribute to meeting the world energy
requirements .
 Emphasis on the production of liquid biofuels (such as ETHANOL AND
METHANOL)via fermentation of agricultural products (such as sugarcane ,
wheat , wood , corn , and agricultural wastes .
 3 important biofuels are ETHANOL produced by Zymomonas and
Thermonerobacter , METHANE by Methanobacterium , and HYDROGEN by
Photosynthetic bacterium .

4. BIOMASS:
 BIOMASS: is the total cellular dry weight or organic material produced by an
organism (usually from CO2 and sunlight ) .
 Biomass includes woods , crops , residues from agricultural and forest products ,
animal waste etc.
 The use of biomass may be :
 direct burning to generate heat (as dung cakes or wood used to yield coal ),
 Thermochemical conversion by PROLYSIS (destructive distillation of wood to
yield coal ) ,.

5.  GASIFICATION (thermal degradation of carbonaceous material to high yield
high amount of gases ).
 by BIOLOGICAL CCONVERSION involving conversions of organic material into
more useful energy forms i.e. gaseous or liquid fuels by using microbes .
 Biological conversions include anaerobic digestion to yield methane (CH4) and
fermentation to produce ethanol

6. DESIRABLE FEATURES OF BIOFUELS :
 They are ECOFRIENDLY .
 Being derived from biomass , which is RENEWABLE .
 They have LOW COST , and are EASILY AVAILABLE saving lot of foreign
exchange for the developing countries .
 The substrate used for biofuels production is often waste which is not only
generates a more valuable product from low cost substrate but also help in
cleaning up the environment .

7. ETHANOL:
 GASOHOL : a mixture of gasoline and ethanol (9:1) . It is an efficient fuel ,
lowering the release of atmospheric hydrocarbon pollutants and can be used
without any engineering modification of the automobile engine .
 Microorganisms used for production of bioethanol : bacteria ( Clostridium ,
Acetobutylium , Leuconostoc , Zymomonas , Sarcina , ) , yeasts (Saccharomyces ,
Aspergillus , Neurospora ).
 Sources used : 1) mainly from – sugarcane , baggase , grain sorghum ,barley
,molasses , maize , corn.
 2) hemp , potatoes , cassava , sunflower , wheat straw , cotton and other
biomass .

8. (production protocol):

9. BIODIESEL :
 BIODIESEL : is a renewable fuel that is made from methyl or ethyl ester of fatty
acids (made from pure or used vegetable oils – edible and nonedible , animal
fats and algae ) or from hydrocarbons produced by some plant and algae .
 BIODIESEL is biodegradable and nontoxic and typically produces about 60%less
net CO2 emissions than petroleum based diesel , as it is itself produced from
atmospheric CO2 via photosynthesis in plants .
 It is a light to dark yellow liquid .
 It is immiscible with water , has a high boiling point and low vapour pressure.

10.  Typical methyl ester biodiesel has a flash point of ~150C making it rather non –flammable .
 Biodiesel uncontaminated with starting material can be regarded as nontoxic.
 It has a viscosity similar to diesel produced from petroleum .
 It can be used as an additive in formulations of diesel to increase the lubricity of pure
ultralow sulphur diesel (ULSD ) fuel , advantage because it has no sulphur content .
 It can be used as heating fuel in domestic and commercial boilers.
 SOURCES USED : VARIETY OF OILS such as soyabean and rapeseed , mustard , flax , palm
palm oil , hemp, algae , sunflower , canola .
 Soyabean oil alone account for ~90% of all fuel stocks used for producing biodiesel .

11. BIOGAS:
 BIOGAS is primarily produced by anaerobic microorganisms , primarily by methane .
 Also known as ( SWAMP , LANDFILL , MARSH , DIGESTER ) gas .
 Produced through METHANOGENESIS by a group of strictly anaerobic archea called
METHANOGENS.
 It is an important fuel used in generation of mechanical , electrical , and heat energy .
 E.g. : melhanobacterium , methanococcus , methanosarcina .
 It can be used as a fuel source for homes and industry and can also be converted by
microbial action or chemical means to methanol which csn be used as a fuel in internal
combustion engines.
 It is a greenhouse gas and its over production in nature may significantly promote future
global warming .

12.  In the biogas digestors , the biodegradable feed stock is converted into two useful
products : GAS and DIGESTATE .
 The digestate comprises manure and the remnants of the anaerobic microorganisms .
 SOUCES USED : 1) PLANTS – agricultural wastes , cellulosic waste , lignocelluosic material .
.
 2) ANIMALS – fishery waste , animal dung , cattle dung , house waste , manure from poultry
.

13. BIOGAS PRODUCTION:
COMPLEX ORGANIC MATERIAL
(digestion by various organic matter in anaerobic digester )
SOLUBILIZATION
first stage in which feedstock is solubilised with water
(enzymes to make slurry )
The complex polymers are hydrolysed into organic acids and alcohols by hydrolytic and fermentative
bacteria .
 (cellulose starch [protein , lipids , nucleic acids ] feedstock organic acid +ethanol.

14. ACIDOGENESIS
Second group of bacteria i.e. Facultative bacteria and hydrogen producing bacteria
Facultative H2 producing bacteria
 Organic acids acetate +H2+CO2.
METHANOGENESIS
Methane producing bacteria
 Acetate +CO2+H2 CH4+H2O+CO2

15. ADVANTAGES OF BIOFUELS :
 EFFICIENT FUEL :
• BIOFUEL is made from renewable resources and relatively less-flammable compared to fossil diesel. It
has significantly better lubricating properties.
• It causes less harmful carbon emission compared to standard diesel. Biofuels can be manufactured from
a wide range of materials. The overall cost-benefit of using them is much higher.
 COST EFFICIENT:
• As of now, biofuels cost the same in the market as gasoline does. However, the overall cost-benefit of
using them is much higher. They are cleaner fuels, which means they produce fewer emissions on
burning. With the increased demand for biofuels, they have the potential of becoming cheaper in the
future as well.
 DURABILITY OF ENGINES :
 Biofuels are adaptable to current engine designs and perform very well in most conditions.

16. • It has higher cetane and better lubricating properties. When biodiesel is used as a combustible fuel, the
durability of the engine increases.
 EASY TO SOURCE :
• Biofuels are made from many different sources such as manure, waste from crops, other byproducts, algae
and plants grown specifically for the fuel.
 RENEWABLE:
• Since most of the sources like manure, corn, switchgrass, soybeans, waste from crops and plants are
renewable and are not likely to run out any time soon, it makes the use of biofuels efficient in nature. Also,
these crops can be replanted again and again.
 REDUCE GREENHOUSE GASES :
• biofuels reduce greenhouse gases up to 65 percent.
• the burning of coal and oil increases the temperature and causes global warming. To reduce the impact
of greenhouse gases, people around the world are using biofuels.

17.  ECONOMIC SECURITY :
• Biofuel production increases the demand for suitable biofuel crops, providing a boost to the agriculture
industry. Fueling homes, businesses and vehicles with biofuels are less expensive than fossil fuels. More
jobs will be created with a growing biofuel industry, which will keep our economy secure.
 REDUCE DEPENDENCE OF FOREIGN OIL:
• As prices of crude oil are touching sky high, we need some more alternative energy solutions to reduce
our dependence on fossil fuels.
 LOWER LEVELS OF POLLUTION :
• As prices of crude oil are touching sky high, we need some more alternative energy solutions to reduce
our dependence on fossil fuels.

18. DISADVANTAGES OF BIOFUEL :
 HIGH COST OF PRODUCTION :
• If the demand increases, then increasing the supply will be a long term operation, which will be quite
expensive. Such a disadvantage is still preventing the use of biofuels from becoming more popular.
 MONOCULTURE:
• Monoculture refers to the practice of producing the same crops year after year, rather than producing various
crops through a farmer’s fields over time. While this might be economically attractive for farmers but growing
the same crop every year may deprive the soil of nutrients that are put back into the soil through crop rotation.
 USE OF FERTILISERS:
• Biofuels are produced from crops, and these crops need fertilizers to grow better. The downside of using
fertilizers is that they can have harmful effects on the surrounding environment and may cause water pollution.
• Fertilizers contain nitrogen and phosphorus. They can be washed away from soil to nearby lakes, rivers or
ponds.

19.  SHORTAGE OF FOOD:
• Using existing land for biofuels may not cause an acute shortage of food; however, it will definitely put
pressure on the current growth of crops.
• One major worry being faced by people is that the growing use of biofuels may just mean a rise in food
prices as well.
 INDUSTRIAL POLLUTION:
• Large scale industries meant for churning out biofuel are known to emit large amounts of emissions and
cause small scale water pollution as well.
 WATER USE :
• Large quantities of water are required to irrigate the biofuel crops, and it may impose strain on local and
regional water resources, if not managed wisely.

20. REFERENCES:
 https://www.conserve-energy-future.com/advantages-and-disadvantages-of-biofuels.php
 https://gevo.com/why-biofuels/biofuel-benefits/
 clid=CjwKCAjw6fCCBhstudentenergy.org/form/biofuels/?gBNEiwAem5SO4nn150pEdzz3vvvki4EM2zCH
o7cFE0nMphqHn8wan3OHN4Lpgnp_RoCaiIQAvD_BwE
 https://www.britannica.com/technology/biofuel