VALUE ADDED PRODUCTS FROM MICROALGAE BIOMASS
APPLYING BIOREFINERY CONCEPTS (AlgaeBioref)
Project title: Value added products from microalgae biomass applying biorefinery concepts
Project code: PN-III-P1-1.1-TE-2019-1842
PNCDI III: Programme 1
Subprogramme: 1.1. Human Resources
Project type: Research Projects for Young Independent Teams (TE)
Contract number: 181PD/2020
Duration: 24 months
Budget: 431.900 RON
Contracting authority: UEFISCDI – Unitatea Executivă pentru Finanțarea Învățământului Superior, a Cercetării, Dezvoltării și Inovării
Coordinating institution: National Institute for Research & Development in Chemistry and Petrochemistry – ICECHIM
The present research proposal aims to obtain high value products (antioxidants, lipids and carbohydrates) from microalgae biomass using the concept of biorefining.
A first stage of this project consists in optimizing the growth conditions of two microalgal strains (Porphyridium purpureum and Dunaliella salina), in order to maximize the content of antioxidants, lipids, carbohydrates, using statistical methods of programming experiments.
The second stage refers to comparing the efficiency of conventional and unconventional extraction methods (supercritical carbon dioxide extraction, ultrasound-assisted extraction and classical solvent extraction) in recovering from wet algal biomass antioxidants and lipid fraction with a high content of fatty acids polyunsaturated (compounds for use in the pharmaceutical industry).
In a third stage, the fractions of lipids rich in polyunsaturated fatty acids and carbohydrates from algal biomass will be transformed into ethyl esters of unsaturated fatty acids and levulinic acid respectively. In order to achieve this transformation, the development of a heterogeneous ferromagnetic acid catalyst is envisaged to ensure the development of these high efficiency processes. By adopting the concept “zero waste, the project aims to convert the exhausted biomass from active principles into biocarbons with adsorbent properties, which will be tested for the retention of inorganic compounds.
The content of the project includes innovative multidisciplinary activities for optimizing the growth conditions of microalgae, respectively for extracting the compounds of interest, and for their efficient transformation into high value added compounds using catalytic systems developed within the project.
O1. Comparison of two microalgae strains and selection of the one that provides the highest amount of antioxidants, lipids and carbohydrates under optimal growth conditions.
O2. Processing of microalgae biomass by conventional and unconventional extraction methods.
O3. Processing the interest compounds extracted from microalgae biomass to synthesize value added chemicals with various application.
WP1. Cultivation, modelling and optimization of algae growth and biomass processing by conventional and unconventional extraction methods
In the first stage, an experimental model of cultivating an algal strain (Dunaliella Salina) was developed in order to select microalgae with a high content of oil and carotenoids. At the end of the exponential growth period, the algal biomass was centrifuged and lyophilized. The algal biomass separated from the culture medium was further processed to obtain the lipid fraction and carotenoid content.
WP2. Microalgal biomass processing by conventional and unconventional extraction methods
During this stage, experimental models were developed for the cultivation of 3 algal strains, in order to select microalgae with a high oil and carotenoid content. At the end of the exponential growth period, the algal biomass was centrifuged and lyophilized. The algal biomass separated from the culture medium was further processed to obtain the lipid fraction and carotenoid content. Due to the very good results obtained, the following two algal strains were selected for further experiments: Porphyridium Purpureum and Chlorella Vulgaris. The algal biomass was further processed by conventional and unconventional extraction methods in order to extract the lipid fraction and pigments (carotenoids). The ultrasonic assisted extraction (UAE) method was used to obtain high extraction yields of carotenoids and lipids. To optimize the extraction parameters different values of intensity (from 60 to 100%), ethanol concentration (25 and 70%), solvent composition (ethanol and hexane concentration ratio to volume ratios of 1: 2; 2: 1 and 1.25 to 1)) and the biomass: solvent ratio (w / v (1: 4 – 1: 8)) were studied. The results obtained can be used for the accumulation and selective extraction of saturated and polyunsaturated fatty acids using food grade solvents. These products can be used in many applications, such as in the food industry and as a lipid supplement. The antioxidant activity of 3 samples was studied: algal biomass of Chlorella vulgaris and Porphyridium purpureum and exopolysaccharides. All 3 samples showed a dependence of the oxidizing activity with the concentration, the highest value being recorded at the highest concentration of 100 μg / ml.
WP3. Processing the interest compounds extracted from microalgae biomass to synthesize value added chemicals
In the last stage, the synthesis of ethyl ester of polyunsaturated fatty acid (PUFAEs) and levulinic acid from carbohidrate fraction and the thermal conversion of de-oil biomass into biochar was followed. A preliminary step to obtaining PUFAEs was the esterification of free fatty acids from microalgae oil with ethanol in the presence of new solid acid catalysts. Parameter optimization (molar ratio oil:alcohol, reaction time, catalyst mass) were obtained using experimental design software. The new efficient solid-acid catalysts prepared was characterized using adequate technics. The transesterification step of pre-treated algae oil with ethanol was realized using a heterogeneous catalyst with hydrotalcite structure. The distribution of PUFAEs and the reaction yield was measured using GC–MS/MS TRIPLE QUAD (Agilent 7890 A).
Levulinic acid (LA) was obtained from the exocarbohydrate fraction from algae biomass, using a stainless steel autoclave purchased in the previous step. For LA synthesis it was tested the same sulfated ferromagnetic acid catalyst prepared previously.
The thermal conversion of de-oil biomass into biochar was performed into the Continuous Flow Tubular Reactor. The major activity was the parameters optimisation (temperature, oxygen concentration and time) in order to obtain a biochar with adsorption properties (characteristics as
porosity, high specific surface area, cation exchange capacity). The porosity, as well as the specific pore area will be was determined by Nova surface area and pore size device. The biochar adsorption capacity for inorganic compounds (e.g Ca, Na, N and P) will be assessed by the application of extended Freundlich isotherm.
National and international conferences
Project Director: Dr. chim. Elena-Emilia Oprescu
Phone: 021 316 30 86