Heterotrophic Microalgae Cultivation for High Lipid Biodiesel
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Solution Overview
Problem
Current methods for producing biodiesel from microalgae face challenges in achieving high saturated fatty acid content, high biomass and oil productivity, and cost-effectiveness, particularly due to contamination and unsuitable lipid profiles from existing microalgal strains.
Innovation Solution
A novel process involving the heterotrophic cultivation of specific green microalgae strains like Chlorella vulgaris, Chlorella kessleri, Botrococcus bruni, Dunaliella salina, and Nannochloris oculata in bioreactors using cheap carbohydrate sources such as wheat flour and organic waste water streams, optimized for high-cell-density growth and lipid extraction, followed by transesterification to produce biodiesel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photoautotrophic cultivation is used, then light penetration and uncontrolled growth conditions limit cell density, but heterotrophic cultivation eliminates light requirement and increases cell density
Solution Approach 1:
The patent changes the cultivation mode from photoautotrophic to heterotrophic by altering the carbon source parameter (from CO2 to organic compounds like glucose), which eliminates the light requirement and enables higher cell density achievement while maintaining process controllability
2Productivity
If heterotrophic cultivation is used, then cell density and lipid productivity increase, but contamination by undesired microbes occurs
Solution Approach 1:
The patent selects specific microalgal strains (Chlorella vulgaris, Chlorella kessleri, Botryococcus braunii, Dunaliella salina, and Nannochloris oculata) that possess inherent resistance to contamination, creating local quality differentiation in strain selection to achieve both high lipid productivity and culture purity
3Quantity of substance
If existing microalgal strains are used, then biomass production is achieved, but saturated fatty acid content is insufficient for biodiesel quality
Solution Approach 1:
The patent changes the cultivation parameters (heterotrophic mode, specific carbon sources, temperature, pH) to induce physiological changes in the selected microalgal strains, which alters the lipid composition to increase saturated fatty acid content while maintaining high biomass production
4Productivity
If expensive carbon sources are used, then high lipid content is achieved, but production cost increases
Solution Approach 1:
The patent replaces expensive carbon sources with cheap alternatives such as glucose, molasses, or agricultural waste hydrolysates, which are inexpensive, readily available, and effectively support high lipid content production in the selected heterotrophic microalgal strains
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process achieves high lipid content up to 58% of dry cell weight, increased saturated fatty acid production, and cost-effective biodiesel production, while inhibiting undesired microbes and maintaining high temperature and pH tolerance.
Implementation Method 1
In heterotrophic conditions algae can be grown on organic carbon sources, such as sugars and organic acids. This mode of culture eliminates the requirement for light and therefore, offers the possibility of greatly increased cell density and productivity.
Implementation Method 2
Large amount of microalgal oil was efficiently extracted from the heterotrophic cells by using n-hexane
Implementation Method 3
The extracted oil was then transmuted into biodiesel by acidic transesterification
Data Source
AI summary
The present invention provides a cost effective biotechnological process for production of bio-fuels from isolated and characterized microalgae. The algal strains used in the present invention having higher biomass, higher lipid productivity, higher pH and temperature tolerance are selected from the group consisting of Chlorella vulgaris iOC-1, Chlorella vulgaris iOC-2, Chlorella kessleri, Botrococcus bruni, Dunaliella salina and Nannochloris oculat or a combination thereof having 95-100% similarity with 18s ribosomal nucleic acids nucleotide sequences (rDNA) given for Seq. ID I, Seq. ID 2, Seq. ID 3, Seq. ID 4, Seq. ID 5 and Seq. ID 6. The present process of bio-fuel production comprises the steps of producing lipid from green algae in bioreactors by various novel steps and extracting oil from dried algal cells and ultimately producing biodiesel by transesterification of the said extracted oil.