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Explora: Environment
and Resource Anabaena-Azolla for crops and bioenergy

residues, grass, sugarcane bagasse, cereal straw, corn cob, and adaptability across diverse environmental conditions,
jatropha, Miscanthus, and alfalfa. These fuels do not need offering a sustainable feedstock for bio-oil production.
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specific land or the application of fertilizers; however, their Bio-oil derived from these systems consists of over 400
processing or extraction costs are higher compared to the oxygenated chemical compounds, including phenolics,
first-generation biofuels. Second-generation biofuels also furanic, sugars, and other solvent oxygenates. Recent
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require pre-treatment of the substrates before fermentation studies have demonstrated that A. filiculoides biomass
to concentrate the fermentable sugars present in the can undergo pyrolysis to produce bio-oil at optimal
substratum. The third-generation biofuels are obtained temperatures ranging from 400°C to 700°C, with the
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from living organisms such as bacteria, yeast, microalgae, maximum bio-oil yield occurring at 500°C. Catalytic
and cyanobacteria. The compounds produced include approaches using magnesium-nickel-molybdenum/
bioethanol, biobutanol, methane, biodiesel, and aviation metal phthalocyanines, modified pyro chars, and other
fuel. Compared to plants, microalgae grow faster and catalysts enhance the yield and composition of these bio-
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require less time for production. They also do not compete oils by altering the proportion of compounds such as furan
with food crops and do not need large amounts of land to derivatives, increasing the viability of the biofuel as a diesel
be grown Genetically modified microorganisms are used substitute. Moreover, these catalytic methods can alter the
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for the production of fourth-generation biofuels. Green composition of pyrolysis products, optimizing their value
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aviation fuels, bio-gasoline, and green biodiesel are some for various bioenergy applications. For instance, research
of the compounds that can be produced from genetically has shown promising results in increasing furan compounds
altered organisms. 88 by up to 33.07% while simultaneously reducing unwanted
Cyanobacteria can synthesize fatty acid-like substances byproducts through catalytic selectivity. This underscores
by utilizing CO . These substances are biodegradable and the significant potential of Azolla-Anabaena-derived bio-
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harmless when used as biofuels. The lipids of cyanobacteria oils in renewable energy applications, particularly as diesel
primarily consist of triglycerides, with smaller amounts of substitutes.
mono- and diglycerides, phospholipids, free fatty acids, Miranda et al. used A. filiculoides, cultivated in
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carotenes, tocopherols, water, etc. This higher amount wastewater, for renewable energy production. After the
of fatty acid content makes cyanobacteria a promising hydrothermal liquefaction of A. filiculoides, the theoretical
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option for biodiesel production. In addition, the presence yield of bio-oil is 20.2 tonnes/ha/year, and bio-char is 48
of cyanobionts in the leaf cavity of Azolla enhances its tonnes/ha/year. In addition, the theoretical yield of ethanol
potential as a source of biofuel. is 11.7 × 10 L/ha/year, which is higher compared to
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Miscanthus, willow, and poplar. As it is grown in synthetic
10.1. Bioenergy production from Azolla wastewater, A. filiculoides accumulates a significant level of
The Azolla-Anabaena symbiotic system presents a selenium, reducing the toxicity of the water. 33
sustainable, cost-effective, and high-yielding platform for
the production of biofuels, including bio-oil and biodiesel. 10.3. Biodiesel extracted from A. Azollae
This mutualistic relationship, in which the cyanobacterium To produce biodiesel from Azolla-Anabaena, Anabaena
Anabaena resides within the aquatic fern Azolla, offers an synthesizes lipids during its photosynthetic and
efficient, sustainable, and scalable feedstock for renewable metabolic processes. These lipids can be harvested and
energy generation. The symbiosis capitalizes on Anabaena’s subjected to transesterification. Experimental studies
ability to fix N , significantly reducing the need for external have demonstrated that A. filiculoides can be effectively
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inputs such as synthetic fertilizers while enabling high processed using solvent extraction with a chloroform-
biomass yield. Recent research has emphasized their methanol solution (2:1 v/v) through Soxhlet extraction
potential in transforming bio-oil and biodiesel through methods to obtain crude oils suitable for biodiesel
innovative extraction methods and thermochemical production. Acid-catalyzed transesterification is a widely
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conversion processes. employed technique that utilizes methanol and catalysts to
convert these lipids into biodiesel. Gas chromatography-
10.2. Bio-oil derived from Anabaena-Azolla mass analysis has confirmed the presence of key fatty
Bio-oil, a liquid fuel derived from the pyrolysis of biomass, acid methyl esters, including palmitic, oleic, and
has emerged as one of the most promising renewable energy stearic acids, in the extracted oils. Furthermore, studies
alternatives. Unlike fossil fuels, bio-oil is carbon-neutral investigating the efficiency of transesterification methods
and produces significantly lower nitrogen and sulfur have demonstrated that the Soxhlet extraction technique
oxide emissions compared to traditional fuels. Azolla- produces higher yields of bio-oil compared to hydraulic
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Anabaena systems exhibit a high biomass production rate pressing methods. The properties of the extracted oils
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Volume 2 Issue 2 (2025) 11 doi: 10.36922/eer.7975