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FAIR-CT98-9664
Production and processing of algae for industrial applications |
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Contract No: | FAIR-CT98-9664 |
| Date Prepared: | July 2001 | |
| Source: | Final Synthesis Report |
Source: Final Report, January 2001
Consortium: The project was co-ordinated by the University of Liege (Belgium) together with Ingenieursburo Innogas bv, Gorinchem (The Netherlands). The Prime Proposer was General Extraction Products GmbH, Flensburg (Germany) and the partners were JOZ bv, Westwoud (The Netherlands), Acide Carbonique Pur NV, Heusden (Belgium), Plukmade Potcultures BV, Made (The Netherlands), Cebeco Handelsraad BA, Rotterdam (The Netherlands), ATO-DLO, Wageningen (The Netherlands).
SYNTHESIS REPORT
Objectives
The objective is to develop a new concept for production (in moderate climate) and processing of algae for industrial and food applications. In addition to identification of an economically feasible production system, products have to be developed for which there is a market demand. Therefore the following objectives were set:
Activities
The second year the project focused on development and construction of a closed cultivation system, consisting of PVC or stainless steel head pieces, plastic tubes placed on the floor and a sophisticated monitoring system. Protocols for disinfection, cultivation and monitoring of growth have been developed and adapted to the new circumstances. Algae have been harvested with a vibrating filtration machine and subsequently dried with a spray dryer. Dried algae have been processed into pasta and cake. Protocols for analysis of compounds and quality analysis of fresh and dried algae have been optimised.
Progress
Several prototypes of a modular closed cultivation system have been developed and constructed. Experience in operating plastic bags and (monitored) closed cultivation systems has been acquired. A vibrating filtration machine consisting of two sieving decks has been tested, followed by laboratory scale spray drying. Market opportunities for Spirulina have been investigated and trials have been performed of products based on the addition of Spirulina to pasta and cakes.
Achievements
A challenge for the consortium was the development of a well-functioning closed cultivation system suitable for a greenhouse. A closed algal cultivation has been developed, constructed and implemented in a way to allow dual use by a quick shift to pot plants and vice versa.
The system consists of modules with PVC head pieces and 'chimneys' to meet pressure changes and to allow easy degassing. In between the head pieces plastic tubes are placed (diameter 6 or 12 cm, length 45m). The algal growth medium is circulated by a pump, in order to prevent deposition of algae in the tubes and to allow degassing of the system (removal of O2). A monitoring system consisting of a computer, software and sensors has been installed. Especially in closed systems it is very important to control temperature, pH and oxygen concentration in the tubes. If, for instance, the temperature rises above 38°C, a whole module with algae can be lost.
In the final prototype, algae can be produced in the separate modules in a controlled way with a low chance of infection. The ALPRO consortium managed to obtain good insight in closed cultivation of Spirulina in just one year.
Three different strains of Spirulina platensis have been grown and further purified. The process was scaled up from 10 l cultures via 80 1 plastic bags to pilot scale closed systems (5,500 - 11,000 1). Tests have been performed in plastic bags to validate the disinfection of rain water with NaOH, to prevent re-infection of the cultures and development of an alternative medium (medium based on liquid dissolved components instead of solids). Protocols for cultivation in the greenhouse have been developed (medium preparation, sampling from bags, parameters to be monitored).
Algae produced in the plastic bags and in the first closed systems have been harvested by filtration of the cultures on a nylon filter cloth. When continuous growth was achieved in the closed systems, a SWECO filtration machine consisting of two sieving decks has been tested. Material from plastic bags could be harvested perfectly with the machine as filtration occurred fast and concentrated slurry was obtained. Due to the small fragment length of material from the closed systems (caused by pumping), harvesting was not very efficient. Harvested material has been dried with a laboratory spray dryer.
Methods for determination and conservation of valuable compounds have been further developed and optimised. Contents of the algae have been determined (proteins, carbohydrates, fatty acids, pigment concentration). In addition, quality tests have been performed. These revealed that Spirulina from the Plukmade greenhouse met the international standards for food grade Spirulina in terms of presence of bacteria, heavy metals and moisture content. Tests on presence of pesticides will have to be carried out in order to complete the quality tests.
Spirulina can be used in several applications, in the form of tablets, as colorant in pasta or cakes or as Novel Protein Food (meat replacement in ready-to-eat meals). Spirulina can be added to pasta, without significantly affecting the original cooking qualities. Up to 4-5 % addition of Spirulina is acceptable for consumers regarding taste and colour.
Other possibilities are to add Spirulina as an ingredient in sport drinks or health snacks. Spirulina may also be added to pet feed (dogs, cats) and to feed for pigs, cattle and chicken.
The extraction phycocyanin (blue natural colourant, fluorescent dye) and gamma-linolenic acid (healthy fatty acid) are worth considering.
Economics
The economics have been worked out on the basis of investment costs (depreciation and interest) for the cultivation and monitoring system, equipment for harvesting and drying, laboratory equipment and variable costs: plastic tubes, water, CO2, nutrients, labour, greenhouse use, energy costs (including drying) and maintenance.
Assuming a yield of 32 ton algae/ha and a selling price of 12.5 Euro/kg, a yearly profit of Euro 8,000 has been calculated. However, when the algal cultivation is well controlled and more experience has been gained on operating and adjusting closed systems, a higher yield should be possible. For a yield of 40 tons/ha profits are to be expected to be around Euro 105,000/year.
Future activities
During 2001 the growth of Spirulina in the prototype closed cultivation system will be monitored throughout the growth period from March to October. Various harvesting regimes will be investigated and several drying trials will be carried out.
To determine economic feasibility, growth data and cost factors have been derived from a small production site and extrapolated to a one ha site. As economic feasibility is dependent on several dynamic parameters, information needs to be up-dated permanently (actual market price, exact costs for optimised cultivation system, achieved yield/ha, possible exploration routes).
Contacts with (potential) processors of algae need to be intensified in order to realise usage of Spirulina in (Western) European meals and/or feed products. It is important to further study relevant properties of algal biomass and methods to modify these properties according to the needs for a specific application.
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