Biomasse pour le futur

Biomass For the Future-BFF in a nutshell

The main aim of BFF was to optimize the production of ligno-cellulosic biomass from miscanthus and sorghum as part of the goal to reach the EU objective “zero CO2 emission” in 2050 in a context of climate change and the replacement of fossil carbon.

BFF has contributed to the development of new miscanthus and sorghum biomass end-uses for energy (combustion, anaerobic digestion) and materials (polymer composites for automobile parts and construction materials), which are complementary to those of food and feedcrops. In this way, BFF is contributing to the creation of local value chains as part of an emerging bioeconomy.

BFF has introduced more genetic diversity into miscanthus and sorghum breeding programs.

BFF has developed genomic approaches to accelerate the creation of new varieties for these species, with a particular focus on yield, sustainability and a biomass quality adapted to the targeted industrial processes.

Results and benefits of BFF

BFF has created a durable multidisciplinary (material science, plant genomics, chemistry, ecophysiology, agronomy, bio-process engineering and life cycle analysis (LCA)) and multisector (public research, farmers, industrials and local governments) community around the production and utilization of sorghum and miscanthus biomass.

Biomass utilization

Anaerobic digestion:  Sorghum genotypes, cultivation, storage conditions and pretreatments were evaluated for their impact on biogas yield either in Biological Methane Potential (BMP) tests or in codigestion with bovine manure in batch leach-bed reactors. In addition, a convenient near infra-red spectroscopy based calibration was developed enabling a high throughput prediction of BMP values of sorghum and miscanthus biomass. LCA analysis shows several scenarios for methane production with a favorable environmental impact. The NIRs screening tool and the genotypes with optimal BMP can now be used in breeding programs.

Polymer-composites for automobile parts: BFF has developedmiscanthus-polypropylene composite formulations for automotive parts with favorable technical characteristics and environmental impact. One formulation, validated by Peugeot-Citroen, is now ready for commercialization. The comparison of various composite preparations from miscanthus, sorghum and maize stems has allowed compositional parameters influencing the mechanical properties of the composites to be identified.

Concrete building blocks: The study of the interaction between concrete and biomass also has identified key compositional parameters that affect the mechanical properties of the concrete. Based upon this knowledge, BFF has developed a simple method for the preparation of miscanthus concrete with a rupture resistance higher than 6MPa, which is suitable for the production of load-bearing blocks. LCA however, shows an unfavorable environmental performance. At this stage it is possible however, to produce non-load bearing concrete blocks with a favorable environmental impact.

Logistics: BFF has developed a decision making software tool for modeling of the biomass price and environmental impact at each step of the value chains.

Agronomy and genetics

Genetic diversification of miscanthus: To diversify the varietal offer, we focused on the species M. sinensis for its high genetic diversity and its excellent adaptability to diverse environments.  The performance of a population of M. sinensis was comparedwith that of Mxg in small-scale field trials at 8 different sites from 2013 to 2019. M. sinensis showed on average a lower yield but a higher site/year yield stability relative to Mxg, whichcould be explained by its higher developmental plasticity. The recycling of nitrogen into the rhizome during the senescence of the aerial parts was equally efficient among the genotypes tested, thus reducing the need for fertilizers. It was also observed that both Mxg and M. sinensis crops promote the accumulation of carbon in the upper soil layers, which contributes to their positive environmental footprint. Finally, BFF has contributed to the development of new triploid Miscanthus sinensis hybrids, which are, like Mxg, sterile and non-invasive. To this end, new tetraploid parents were generated through tissue culture and crossed with diploid parents. The triploid offspring is currently being evaluated in a nursery.

Genetic diversification of sorghum: Three approaches were used to increase the diversity of the elite germplasm used for hybrid production. (1) A factorial breeding design based on 10 females and 16 male elite lines from CIRAD, EUROSORGHO and RAGT2N was evaluated in 3 crop management systems. Although this failed to identify superior hybrids relative to the commercial industrial references, it provided important new insights into the genetic determinism of target traits and the contributions of the male and female pools to the hybrid values. In addition, it provided experimental hybrids specifically targeting early sowing dates (to avoid mid-summer drought stress) and double cropping systems. (2) A marker-assisted recurrent selection in a multi-parental scheme (G2Mars) involving 7 connected populations (2 males, 3 females and one connecting population) was developed for 1200 F4 families. These families were characterized on two sites in topcross evaluations and the best crosses to perform among the F4 populations were identified. Several male and female genotypes have been integrated in the double purpose breeding programs. (3) To increase the diversity of the female elite pool, which currently is extremely narrow, exotic alleles were introduced via a Back Cross Nested Association Mapping population (BCNAM). Two elite female recurrent parental lines from the two private breeding programs were crossed with a set of 10 donor genotypes highly contrasted in terms of biochemical composition. A total of 2000 BC1F4 families were established, genotyped and phenotyped for yield and biomass composition. Several BC1F5 lines are now being used in the breeding programs.

Quantitative genomics in support of accelerated breeding: The long-term objective is to accelerate the breeding process by using genomic selection approaches combined with the decomposition of complex traits and knowledge about gene function. This should provide markers for early selection for combinations of traits that normally become scorable only after months, and for miscanthus, even after years, of field monitoring. To support these approaches, BFF has worked out powerful medium- to high-throughput methods for the screening of biomass composition and histology. In addition, large scale screening of different sorghum genotypes in field trials under varying conditions has allowed the development of modeling tools that decompose yield and biomass composition in a number of parameters from which “ideal” plant varieties (ideotypes) can be predicted in silico. The same parameters can be used as selectable traits in breeding programs.

The genotyping and phenotyping of large panels of field-grown sorghum and maize accessions and mapping populations has allowed the identification of QTLs for agronomic and quality traits, including loci connecting drought stress to improved biomass digestibility. Given the close taxonomic proximity of maize, sorghum and miscanthus, QTLs conserved between maize and sorgum are also good candidates for the imporvement of miscanthus. Finally, the mapping, gene annotations and transcriptomic analysis provides functional information, which will improve the predictive power of the genomic selection.

Concerning miscanthus, hundreds of wild M. sinensis accessions were collected and 2 F1 mapping populations were generated and grown at 2 different locations. The phenotyping over 5 years has allowed the heritability of various agronomic and quality traits to be determined and the identification of QTLs for flowering time and biomass-related traits. Genome editing methods are being developed to create, in miscanthus, specific mutant alleles corresponding to favorable alleles in maize or sorghum.

Overall, besides the above-mentioned scientific and technological progress, described in over 60 publications, BFF has laid the groundwork for 26 national and international projects that will controbute to the emergence of a bioeconomy.