PRIN 2022 / Sforza

LOGO INTESTAZIONE PRIN 2022

Acronimo: LUCE
Titolo: Lignin Utilization to Cultivate Engineered microalgae for polysaccharides accumulation
Responsabile scientifico: Prof.ssa Eleonora SFORZA - Dipartimento di Ingegneria Industriale-Università' degli Studi di PADOVA
Coordinatore: Prof. Matteo GIGLI - Università "Ca' Foscari" VENEZIA
Partner-Unità di ricerca: Università degli Studi di Verona, Dipartimento di Ingegneria Industriale-Università degli Studi di PADOVA
Bando: PRIN 2022 - Decreto Direttoriale n. 20432 del 06-11-2024
Durata: 04/02/2025 - 03/02/2027 (24 mesi)
Budget totale progetto: € 86.912,00

Abstract del progetto

"Can technical lignins be employed to boost the production of polysaccharides by microalgae?" This is the fundamental question the LUCE project will answer to. The idea arises from the fact that technical lignins (TL), produced in huge amounts as by-product of pulp and paper industries and modern biorefineries, are largely burned for energy production, mainly due to their structural complexity and variability that hamper a full valorization into marketable products. Thus, finding alternative, more economically and environmentally sustainable exploitation strategies is of outmost importance. In this respect, the production of polysaccharides by photosynthetic microorganisms stimulated by the presence of TL would represent an unprecedented, yet highly favorable solution. Among the polysaccharides, cellulose, especially in its nanostructured form, is a high value-added material of choice for a broad range of applications ranging from flexible electronics to bio(nano)medical devices. To achieve the LUCE goal, two research lines will be implemented: 1) metabolic engineering and cultivation of Synechococcus PCC 11901 (Sc) and 2) optimization of lignin-based growth stimulation of Euglena gracilis (Eg). In line 1 Sc, a newly-discovered fast-growing species belonging to a genus that accumulates cellulose, will be used to: a) improve the capability of using TL by genetic approaches; b) increase the yield of native cellulose by metabolic engineering; c) assess the effect of operating variables on the cultivation of microalgae, accumulation of cellulose and exploitation of TL. In line 2 Eg, where the beneficial action of a specific class of TC, i.e. lignosulfonates (LS), was very recently reported, will be used to enhance the production of paramylon. Eventually, a collection of Eg random mutant strains will be generated and screened in continuous systems for improved biomass productivity in the presence of TL-derived growth-stimulating compounds. Mass and energy balances will be applied to implement kinetic models and process simulation. Various TL will be tested as growth-promoting agents. To evaluate the physicochemical features of the molecules involved in the microalgae growth, lignin model compounds will be synthesized and TL will be fractionated by physical means into more homogenous cuts. Additionally, specific protocols will be adopted to achieve TL solubility in the conditions used for microalgae cultivation to overcome any possible availability limitations. The obtained microalgal biomass will be processed to extract and comprehensively characterize polysaccharides, lipids and pigments (carotenoids, phycocyanin, chlorophylls). Extractions will be performed exploiting green approaches such as scCO2, microwaves, ultrasounds, enzymes and synergistic combinations thereof. Innovative valorization strategies for the extracted compounds will be envisaged and tested. A preliminary techno-economic assessment will support the overall process sustainability.