Biorefinery of Cannabis sativa using one- and two-step steam treatments for the production of high quality fibres

Among the sources of lignocellulosic biomass that could be considered as a feedstock for a biorefinery, hemp (Cannabis sativa) is known for the quality and relative abundance of its fibre. In this work, two variations of the Feedstock Impregnation Rapid and Sequential Steam Treatment (FIRSST) process are compared for the production of both fibres and biomolecules (including liquid fuels) as the valorization of the entire carbon content of biomass is needed to reach economical viability. In the first variation, the fibres were isolated via two specific and sequential steam treatments while in the second variation, fibres were isolated using only one steam treatment. Both processes allowed the isolation of a fibre that was comparable to kraft pulp while reducing the amounts of ashes along the process. Compositions of the residual solid fibre at different steps of the treatment were evaluated using ASTM and TAPPI standard methods. Carbohydrates were identified and quantified using HPLC with an anion exchange stationary phase. The qualities of the FIRSST and Kraft pulp produced were compared using standard ATPPC methods. Both pulps showed similar indexes. The two-steps FIRSST process has leaded to direct isolation of cellulose, hemicelluloses and lignin that could be suitable for the production of energy (biofuels) and high value chemicals, with small investments in terms of chemicals and energy.

► We compared one- and two step steam treatments for Cannabis sativa fractionation.
► Two-step steam treatment allows an efficient fractionation.
► We recovered relative pure hemicelluloses, lignin, cellulose and extractives.
► High quality fibers were obtained using one- and two step steam treatments.
► Cannabis sativa can be used for the production of pulp or ethanol.