# Effective Use of Flax Biomass in Biorefining Processes
## 4 Conclusions  
In this study, five lines of linseed, four lines of dual purpose and three lines of fiber flax were analyzed, and based on the biometric measurements, one genotype for each form of flax was selected, i.e., linseed--PET 16/16, dual purpose--SW 16/13 and fiber flax--PET 16/20. The obtained values of straw weights for all three forms of flax testify to the significant potential of selected genotypes to produce a large amount of raw material for biorefining processes.  
In the next stage, the variety of flax with the greatest energy potential was selected. It was found, based on the content of reducing sugars obtained after alkaline pretreatment, that all selected forms of flax can be an effective raw material for bioethanol production, especially fiber flax, for which 8.72 g:L-1 of ethanol was obtained. These results indicate the possibility of expanding the raw material base to produce 2G bioethanol.  
Whereas, the biomass fillers of the three tested varieties of flax caused a decrease in the bioccomposite's tensile strength by several percent compared to the biodegradable PLA polymer and a significant increase in the modulus of elasticity in the range of 53-60%. In addition, the susceptibility of bioc Composites containing flax biomass to the action of mold fungi in relation to pure PLA was demonstrated. Biocomposites with fiber flax biomass were the most susceptible to the tested fungi and showed the greatest changes in mechanical properties. The lowest susceptibility to test fungi and the smallest changes in strength were observed for samples of bioc Composites with linseed biomass. The obtained results can be the basis for the design of modern biocomposites with the assumed properties depending on the target application, e.g., packaging for food products (vegetables, fruit), elements of equipment for public transport vehicles and elements of furniture and interior design used in public places.  
On the basis of the conducted research, the possibility of using flax biomass, in particular fiber flax biomass, for valuable bioproducts--bioethanol and \"green\" composites, and for each tested form of cultivated flax, the possibility of profitable use of the collected seeds was demonstrated.  
Conceptualization, J.B., A.W., M.P., K.B. and J.F.-F.; Methodology, J.B., A.W., M.P., K.B. and J.F.-F.; Software, A.W., W.G.; Validation, J.B., A.W., M.P., K.B. and J.F.-F.; Formal analysis, J.B.; Investigation, A.W., W.G., M.C., K.B., S.R. and J.F.-F.; Resources, J.B., A.W., W.G., M.P., M.C., K.B., S.R. and J.F.-F.; Data curation, J.B., A.W., W.G., M.P., M.C., K.B., S.R. and J.F.-F.; Writing--original draft preparation, J.B., A.W., W.G., M.P., K.B. and J.F.-F.; Writing--review and editing, J.B. and A.W.; Visualization, J.B.; Supervision, J.B.; Project administration, J.B. and M.P.; Funding acquisition, J.B. and M.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Polish Ministry of Agriculture and Rural Development as part of the grant awarded to the Institute of Natural Fibres and Medicinal Plants in 2022/23.  
Not applicable.  
The study was conducted as a research project--Grant: Area 2. Assessment of the potential of fiber and herbal plants in terms of their applicability in various areas of bioeconomy. Task 2.1. Assessment of the application potential of flax and hemp according to the principle of cascade use of fiber plants. Ministry of Agriculture and Rural Development, Poland (2021); research project--Production of initial materials for breeding of flax new varieties with improved quality and increased resistance to _Fusarium_ spp. and drought. Ministry of Agriculture and Rural Development, Poland (2022-2023).  
The authors declare no conflict of interest.