Changes in the structure and composition of pineapple leaf fiber after alkali and ionic surfactant pretreatments and their impact on enzymatic hydrolysis.

The current study investigated the effects of two different pretreatments (NaOH and alkaline surfactant assisted) on the chemical, morphological and enzymatic saccharification of pineapple leaf fiber (PALF). Results showed that both pretreatments significantly reduced lignin content of the biomass, achieving a 69.6 and a 76.3% reduction for NaOH and surfactant pretreated materials, respectively. SEM, CLSM and FTIR-ATR techniques were used to evaluate morphological changes in the fibers after pretreatments. Images obtained revealed cellulose exposure and lignin redistribution in the pretreated fibers. Surfactant pretreated material provided the best results after enzymatic hydrolysis compared to NaOH and untreated PALF. A final enzymatic hydrolysis yield of 81.8% was obtained after a 24 h process using surfactant pretreated fibers, in comparison to 75.9 and 45.1% yields for NaOH pretreated material and raw fibers, respectively. Nowadays, the use of agricultural residues for high added value products is of great importance for sustainable development. This work specifically studied an effective and green approach for lignin removal and enzymatic hydrolysis from pineapple leaf fiber that is an abundant waste in Costa Rica and an interesting feedstock for biorefinery processes design.

Wood-Decaying Fungi: From Timber Degradation to Sustainable Insulating Biomaterials Production.

Addressing the impacts of climate change and global warming has become an urgent priority for the planet's well-being. In recent decades the great potential of fungal-based products with characteristics equal to, or even outperforming, classic petroleum-derived products has been acknowledged. These new materials present the added advantage of having a reduced carbon footprint, less environmental impact and contributing to the shift away from a fossil-based economy. This study focused on the production of insulation panels using fungal mycelium and lignocellulosic materials as substrates. The process was optimized, starting with the selection of Trametes versicolor, Pleurotus ostreatus, P. eryngii, Ganoderma carnosum and Fomitopsis pinicola isolates, followed by the evaluation of three grain spawn substrates (millet, wheat and a 1:1 mix of millet and wheat grains) for mycelium propagation, and finishing with the production of various mycelium-based composites using five wood by-products and waste materials (pine sawdust, oak shavings, tree of heaven wood chips, wheat straw and shredded beech wood). The obtained biomaterials were characterized for internal structure by X-ray micro-CT, thermal transmittance using a thermoflowmeter and moisture absorption. The results showed that using a wheat and millet 1:1 (w/w) mix is the best option for spawn production regardless of the fungal isolate. In addition, the performance of the final composites was influenced both by the fungal isolate and the substrate used, with the latter having a stronger effect on the measured properties. The study shows that the most promising sustainable insulating biomaterial was created using T. versicolor grown on wheat straw.