acids from vegetable oils and animal fats, for use in ignitioncompression
engines (diesel). It is a renewable, biodegradable and
non-toxic biofuel. The depletion of fossil fuel reserves, together
with heightened awareness of climate change and contaminant
emissions, have led to increased interest in biodiesel as a potential
alternative to fossil fuels (1,2).
Compared to the two previous generations of biodiesel feedstocks
(i.e., food and non-food crops), the third generation, microalgae,
has appeared to be a suitable energy source for biodiesel
production. Algae use sunlight to produce oils, but they do so more
efficiently than crop plants due to their higher productivity (3).
Moreover, some species can accumulate large amounts of lipids and
they do not need high quality agricultural land or even high quality
water to grow biomass. However, the production cost of high grade
algae oils constitutes an obstacle in the short term. The main reason
is that the operational conditions leading to high grade oil in
microalgae are usually those providing low growth rates (low
temperature, low light intensity and nitrogen deficiency) (4). Use of
the biorefinery concept will help to lower the cost of production.
Like a petroleum refinery, a biorefinery uses every component of
the biomass raw material to produce useable products (3).