Keywords Microalgae Á Process intensification Á Biofuels Á Biorefinery
Reactor designs
1 Introduction
1.1 Need of Biofuels
Greenhouse gases (GHG) are mainly produced by the transportation and
energy-producing sectors. Along with GHG, other pollutants like SO x , NO x , CO,
volatile compounds, and particulate matter are also released into the atmosphere.
Day by day, the global energy consumption is increasing, also resulting in an
increase in pollution which further raises the concern of global warming. To cope up
with the energy requirements and at the same time reduce the pollution, development
of sustainable alternative energy sources has become the major goal. Many countries
are working on utilizing different alternatives like solar energy, geothermal, wind,
hydroelectric, thermal or photovoltaic, and biofuels. Every alternative generally
comes with its own pros and cons, and the development of optimum and feasible
alternative with time is the desired solution. Among the biofuels, Second-generation
biofuels (biodiesel, bioethanol, and biogas) offer important alternatives and can be
produced from sustainable resources available, with lesser or practically no emissions on their combustion. Biodiesel can be produced from non-edible oils, waste
cooking oil, waste grease, or animal fats, whereas bioethanol and biogas can be
produced from agricultural waste (wheat straw, corn cobs, etc.) and other sustainable
materials. The availability of these materials, expensive processing, and production
cost cannot fulfill the current supply and demand of energy requirements in a most
efficient manner. Biofuel production from microalgae which comes under
third-generation biofuels has now become a significant research area. Advantages
like easy cultivation, non-competitiveness with food supply chain, higher lipid
content, and less processing are obtained based on the use of microalgae which help
in overall reduction of biofuel production cost.
1.2 Microalgae
Microalgae are unicellular microscopic organisms found in both marine and
freshwater environment. They perform photosynthesis with efficiency higher than
that of crops and consist of various components which can be utilized for many
commercial purposes such as in the food, cosmetic, and high-value specialty
molecules industry. Capability to naturally produce many unusual and different fats,
bioactive compounds, sugars, etc., comes from their diversified genetic group
which also comes with different physiological and biological characteristics.
Microalgae mainly consist of proteins, carbohydrates, fats, and nucleic acids which
60
S. Joshi and P. Gogate
Reactor designs
1 Introduction
1.1 Need of Biofuels
Greenhouse gases (GHG) are mainly produced by the transportation and
energy-producing sectors. Along with GHG, other pollutants like SO x , NO x , CO,
volatile compounds, and particulate matter are also released into the atmosphere.
Day by day, the global energy consumption is increasing, also resulting in an
increase in pollution which further raises the concern of global warming. To cope up
with the energy requirements and at the same time reduce the pollution, development
of sustainable alternative energy sources has become the major goal. Many countries
are working on utilizing different alternatives like solar energy, geothermal, wind,
hydroelectric, thermal or photovoltaic, and biofuels. Every alternative generally
comes with its own pros and cons, and the development of optimum and feasible
alternative with time is the desired solution. Among the biofuels, Second-generation
biofuels (biodiesel, bioethanol, and biogas) offer important alternatives and can be
produced from sustainable resources available, with lesser or practically no emissions on their combustion. Biodiesel can be produced from non-edible oils, waste
cooking oil, waste grease, or animal fats, whereas bioethanol and biogas can be
produced from agricultural waste (wheat straw, corn cobs, etc.) and other sustainable
materials. The availability of these materials, expensive processing, and production
cost cannot fulfill the current supply and demand of energy requirements in a most
efficient manner. Biofuel production from microalgae which comes under
third-generation biofuels has now become a significant research area. Advantages
like easy cultivation, non-competitiveness with food supply chain, higher lipid
content, and less processing are obtained based on the use of microalgae which help
in overall reduction of biofuel production cost.
1.2 Microalgae
Microalgae are unicellular microscopic organisms found in both marine and
freshwater environment. They perform photosynthesis with efficiency higher than
that of crops and consist of various components which can be utilized for many
commercial purposes such as in the food, cosmetic, and high-value specialty
molecules industry. Capability to naturally produce many unusual and different fats,
bioactive compounds, sugars, etc., comes from their diversified genetic group
which also comes with different physiological and biological characteristics.
Microalgae mainly consist of proteins, carbohydrates, fats, and nucleic acids which
60
S. Joshi and P. Gogate