Many agricultural residues can be converted to energy products (bioethanol, biogas) and chemicals, polymers. In fact, these materials are largely made up of biopolymers (hemicellulose, cellulose and lignin) that appropriately destructured can form the basis of a large chemical synthesis and fermentation processes that are crucial in the view of Bioeconomy. The residues of maize cultivation, after the production of kernels (stalks, cobs, leaves), are particularly interesting, both for their composition and for being largely available in the temperate zones. We can say that from the point of view of productivity and the impact on food and agriculture, the corn plant plays a role analogous to that of sugar cane plays in the agricultural economy of the tropics. This is why we chose this remnant; It is to be considered, however, that the deductions can be applied with a great margin of reliability also to other types of lignocellulosic residues. The experiments covered the recovery of sugars from carbohydrate of the lignocellulosic material, after their separation through a pretreatment process, ie Steam Explosion (SE), which uses saturated steam in a temperature range between 180 - 200 ° C. This pretreatment is among the most used both in laboratory and in industrial scale because it is effective, economical and has low environmental impact. The SE treatments were carried out in a 10-liter batch reactor able of processing about 1 kg of wet biomass per cycle. The investigated parameters were temperature and the degree of pre-impregnation with sulfuric acid added to catalyze the hydrolysis reactions. The optimization of the number and type of treatments to find the optimal conditions and the statistical analysis of data was performed using specific software of DoE (design of experiments). The experimental data showed that the maximum recovery of carbohydrates can be obtained using a load of sulfuric acid of 2.9% and a temperature of 180 °C (at 5 minutes of treatment). In particular, the action of sulfuric acid amplifies the hydrolytic effects of the treatment of SE further fragmenting the polymers of the biomass in water soluble oligomers and monomers. Furthermore, its use is particularly useful at low temperatures since it increases the solubilization of biomass, especially in the case of xylose that is solubilized up to 80%.
Molti residui agricoli possono essere trasformati in prodotti energetici (bioetanolo, biogas) e intermedi dell’industria chimica e dei polimeri. Infatti, questi materiali sono costituiti in gran parte da biopolimeri (emicellulosa, cellulosa e lignina) che opportunamente destrutturati e isolati possono costituire la base di una ricca chimica di sintesi e di processi fermentativi che sono fondamentali nella visione della Bioeconomy. I residui della coltivazione del mais a valle della produzione delle cariossidi (stocchi, tutoli, foglie), sono particolarmente interessanti, sia per la composizione sia per la relativa diffusione in Italia e nelle zone temperate in generale. Volendo stabilire un paragone, si può dire che dal punto di vista della produttività e dell’impatto sull’industria agroalimentare, la pianta del mais riveste un ruolo analogo a quello che la canna da zucchero riveste nell’economia agricola delle zone tropicali. Questo è il motivo per cui abbiamo scelto questo residuo; è da considerare comunque che le deduzioni tratte possono essere applicate con un ottimo margine di affidabilità anche ad altri tipi di residui lignocellulosici. Le sperimentazione condotta ha riguardato il recupero di zuccheri dai carboidrati costituenti il materiale lignocellulosico, previa loro separazione attraverso un processo di pretrattamento, ossia Steam Explosion (SE), che utilizza vapore saturo in un intervallo di temperatura compreso tra 180 - 200 °C. Questo pretrattamento è tra i più utilizzati sia in scala laboratorio che in impianti industriali perché è efficace, economico e a basso impatto ambientale. I trattamenti di SE sono stati eseguiti in un reattore batch da 10 litri capace di processare circa 1 kg di biomassa umida per ciclo. I parametri esaminati sono stati la temperatura del processo e il grado di pre-impregnazione con acido solforico, aggiunto per catalizzare le reazioni di idrolisi. L’ottimizzazione del numero e del tipo dei trattamenti per ritrovare le condizioni ottimizzate e l’analisi statistica dei dati sono stati eseguiti utilizzando specifici software di DoE (design of experiments). I dati sperimentali hanno mostrato che la massima solubilizzazione dei carboidrati può essere ottenuta utilizzando un carico di acido solforico del 2.9% ed una temperatura di 180 °C ad un tempo di trattamento di 5 minuti. In particolare, l’azione dell'acido solforico amplifica gli effetti idrolitici del trattamento di SE frammentando ulteriormente i polimeri della biomassa in oligomeri e monomeri idrosolubili. Inoltre, il suo impiego risulta particolarmente utile a basse temperature dato che incrementa la solubilizzazione della biomassa, soprattutto nel caso dello xilosio che viene solubilizzato all’80%.
Recupero di zuccheri da residui agricoli
Viola, E.;Larocca, V.;Zimbardi, F.
2016-06-01
Abstract
Many agricultural residues can be converted to energy products (bioethanol, biogas) and chemicals, polymers. In fact, these materials are largely made up of biopolymers (hemicellulose, cellulose and lignin) that appropriately destructured can form the basis of a large chemical synthesis and fermentation processes that are crucial in the view of Bioeconomy. The residues of maize cultivation, after the production of kernels (stalks, cobs, leaves), are particularly interesting, both for their composition and for being largely available in the temperate zones. We can say that from the point of view of productivity and the impact on food and agriculture, the corn plant plays a role analogous to that of sugar cane plays in the agricultural economy of the tropics. This is why we chose this remnant; It is to be considered, however, that the deductions can be applied with a great margin of reliability also to other types of lignocellulosic residues. The experiments covered the recovery of sugars from carbohydrate of the lignocellulosic material, after their separation through a pretreatment process, ie Steam Explosion (SE), which uses saturated steam in a temperature range between 180 - 200 ° C. This pretreatment is among the most used both in laboratory and in industrial scale because it is effective, economical and has low environmental impact. The SE treatments were carried out in a 10-liter batch reactor able of processing about 1 kg of wet biomass per cycle. The investigated parameters were temperature and the degree of pre-impregnation with sulfuric acid added to catalyze the hydrolysis reactions. The optimization of the number and type of treatments to find the optimal conditions and the statistical analysis of data was performed using specific software of DoE (design of experiments). The experimental data showed that the maximum recovery of carbohydrates can be obtained using a load of sulfuric acid of 2.9% and a temperature of 180 °C (at 5 minutes of treatment). In particular, the action of sulfuric acid amplifies the hydrolytic effects of the treatment of SE further fragmenting the polymers of the biomass in water soluble oligomers and monomers. Furthermore, its use is particularly useful at low temperatures since it increases the solubilization of biomass, especially in the case of xylose that is solubilized up to 80%.File | Dimensione | Formato | |
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