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Sustainable Algae Biorefinery for Agriculture aNd Aquaculture

Periodic Reporting for period 2 - SABANA (Sustainable Algae Biorefinery for Agriculture aNd Aquaculture)

Reporting period: 2018-06-01 to 2019-11-30

SABANA aims at developing a large-scale integrated microalgae-based biorefinery for the production of biostimulants, biopesticides and feed additives, in addition to biofertilizers and aquafeed, using only marine water and nutrients from wastewaters (sewage, centrate and pig manure). The objective is to achieve a zero waste process at a demonstration scales up to 5 ha sustainable both environmentally and economically. A Demonstration Centre of this biorefinery will be operated to demonstrate the technology, assess the operating characteristics of the system, evaluate environment impacts and collaborate with potential customers for use. The key advantages of SABANA project are: the sustainability of the process, using marine water and recovering nutrients from wastewaters while minimizing the energy consumption, and the socioeconomic benefits, due to the relevance of the target bioproducts for two major pillars in food production as agriculture and aquaculture. Bioproducts capable of increasing the yield of crops and fish production are highly demanded, whereas recovery of nutrients is a priority issue in the EU. Instead of considering wastewater as an inevitably useless and problematic residue of our society, SABANA acknowledges its potential as an opportunity for economically relevant sectors. SABANA project includes (i) the utilization of microalgae-bacteria consortia and in co-culture with other algae to control grazing species, (ii) the implementation of efficient thin-layer cascade and raceway, (iii) the scale-up of reactors to ensure stable operation, (iv) to use marine water to increase the sustainability of the process; (v) to recover nutrients from wastewaters, (vi) to develop harvesting processes taking into account the remaining water, (vii) to establish processes for mild/energy efficient extraction of bioproducts, (viii) to process residual biomass to produce biofertilizers and aquafeed in zero-waste schemes, (ix) using robust and sustainable technology.
From the beginning of the project most of the initial activities planned have been successfully developed. The progress of the project was a little bit delayed due to problems with permissions to build the industrial facility, but finally both the DEMNO1 R&D and the DEMO1 PRODUCTION facilities are now in operation the construction of DEMO5 being started in short time. Most relevant activities already completed includes: (1) initially selected strains have been evaluated for their application on agriculture and aquaculture, a larger set of strains than initially considered being evaluated. Fortunately, a large number of strains demonstrate positive effects as biostimulant and biopesticide, they being also suitable to be grown in wastewaters. Additionally, a large number of strains, including freshwater in addition to marine strains, demonstrate to be useful to improve the quality of aquafeed actually used in aquaculture. Five microalgae and three cyanobacteria have been selected for agriculture applications, whereas three marine and two freshwater microalgae strains have been selected for aquaculture applications. (2) The engineering of the required facilities to produce these strains have completed, DEMO1 R&D and DEMO1 PRODUCTION facilities have been build, DEMO5 being in probgress. The facility includes the photobioreactors and all the auxiliary facilities required. New developments in reducing the environmental impacts of photobioreactors constructions have been validated. These facilities are being used now to determine the performance of previously selected strains at outdoor conditions, to produce samples of biomass for development of processing methods and validation of products, and to provide real data for Data Centre. (3) DEMO1 R&D and DEMO1 PRODUCTION facilities are being used to compare the performance of different harvesting and processing methods. A two-step process using dissolved air flotation (DAF) and nozzle separator is the most promising technology for recovery of biomass at low cost/energy when producing microalgae using wastewater as culture medium, whereas to produce microalgae using clean resources the utilization of non-pressure membrane systems is recommended. Concerning cell disruption, although different technologies have been evaluated, homogenizer is still the most suitable technology at large scale. However, last data using Pulse Electric Field (PEF) also demonstrated that this technology is also suitable, especially to obtain different products (biostimulant+biofertilizers) from the same biomass instead a single end product. (4) Technologies/techniques to monitor and manipulate microalgae cultures have been developed and evaluated, especially when using wastewaters as nutrients source, then a consortium of microalgae and bacteria prevailing. Molecular biology tools are being used to monitor these cultures, in addition other photosynthesis/photorespiration methods, and neural networks among others. (5) Techno-economic and sustainability analysis of developed technologies have been performed. Tools capable to simulate the technical-economic-environmental aspects of whatever microalgae based process have been validated. This work has been completed with the development of adequate methods to determine the social acceptance of microalgae based processes, especially those developed on SABANA project. (6) A Training Centre for education and training, in addition to an open Data Centre for sharing data obtained from real photobioreactors have been developed.
Results from the beginning of the project validate all the premises on which SABANA project was planned. First, the interest of microalgae for agriculture and aquaculture products has been validated. Data included in the corresponding deliverables confirm the high value and interest of microalgae as source of biostimulants and biopesticides. In the case of aquaculture, the necessity of more sustainable sources of proteins and lipids to replace fish oil and fish meal has been previously reported, but this requirement is each time more urgent by the reduction on the availability of wild fish to produce these critical raw materials. Microalgae demonstrated to provide beneficial effects for the fish as prebiotic, including at low inclusion rates of 4%. Techno-economic analysis performed allows confirming that both markets, and including wastewater treatment, are highly promising for microalgae applications. For agriculture related applications microalgae biomass production cost up to 10-20 €/kg are acceptable, whereas for aquaculture related applications maximum biomass production cost up to 2-5 €/kg are acceptable. For wastewater treatment the maximum acceptable biomass production cost is less than 0.2 €/kg (equivalent to 0.2 €/m3 of wastewater). Technology proposed in SABANA project allows to achieve this production cost, by using improved open reactors, adequately managed, and mainly using wastewaters as source of nutrients and low cost harvesting and processing methodologies. The utilization of wastewaters as nutrients source, and in general the optimal design of the process also allows guaranteeing the sustainability of the entire process. Tools developed for the analysis of developed technologies, in addition to its economy and sustainability are highly relevant on this field for the development and validation of new microalgae based-processes.
Equipment for harvesting at DEMO1 R&D scale
Dissemination at Bioeconomy Village
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DEMO1 R&D Facilitie completed
Downstream processing of the biomass
Trials of different harvesting methods
Improved large scale raceway reactor
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Students developing training activities