Browsing by Keyword "Enzymatic hydrolysis"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Biomass Pretreatment Strategies (Technologies, Environmental Performance, Economic Considerations, Industrial Implementation)(Elsevier Inc., 2016-03-01) Peral, Carlota; Alimentación SostenibleAgricultural wastes are the most abundant and renewable resources in the world. These wastes, commonly called lignocellulosic biomass, are composed mainly of cellulose, hemicellulose, and lignin. Both the cellulose and hemicellulose fractions are polymers of sugars and thereby a potential source for fermentation processes. Lignin can be used for many purposes, including production of chemicals, heat, and energy. Lignocellulosic biomass is recalcitrant to hydrolysis with cellulolytic enzymes. Therefore, a pretreatment step is necessary for the production of fermentable sugars. Various pretreatment methods, such as physical, chemical, physicochemical, biological, and combinations of them are available. Selection of the best pretreatment depends on factors as foreseen utilization of the main biomass components, efficiency in separation, environmental concerns, compatibility with subsequent fermentation, energy requirements, and costs that must be taken into account for commercial implementation.Item Protein hydrolysate from organic fraction of municipal solid waste compost as nitrogen source to produce lactic acid by Lactobacillus fermentum ATCC 9338 and Lactobacillus plantarum NCIMB 8826(2020-01) Izaguirre, Jon Kepa; Dietrich, Thomas; Villarán, M. Carmen; Castañón, Sonia; Alimentación SostenibleIn this work a strategy for obtaining free amino-acids concentrate from an organic fraction of municipal solid waste compost and its use as a nitrogen source for lactic acid production, a compound widely used in different industries, using L. fermentum ATCC 9338 and L. plantarum NCIMB 8826 strains is described. Enzymatic digestion is based on the combined action of endoprotease Alcalase 1.5 MG and exoprotease Flavourzyme 500 MG. The highest degree of hydrolysis obtained under the optimal conditions was 41%. The use of glucanase Viscozyme L prior to protein hydrolysis helped to reduce the viscosity of the solution and promote the action of proteases, increasing its hydrolysis degree by 76%. The hydrolysate contained all 21 amino-acids, making it ideal for lactic acid bacteria growth. During shake flask cultivations the culture media was complemented with glucose as carbon source. Finally, with the hydrolysate, a maximum lactic acid concentration of 9.0 ± 0.2 g·L−1 and 11.1 ± 0.1 g·L−1 for L. fermentum ATCC 9338 and L. plantarum NCIMB 8826 respectively was obtained after 27 h. The innovation of the approach lies in exploiting the overproduction of compost for the production of lactic acid.Item Upgrading the organic fraction of municipal solid waste to poly(3-hydroxybutyrate)(2019-10) Izaguirre, Jon Kepa; da Fonseca, M. Manuela R.; Fernandes, Pedro; Villarán, M. Carmen; Castañón, Sonia; Cesário, M. Teresa; Alimentación SostenibleThe organic fraction of municipal solid waste was studied as feedstock for the production of poly(3-hydroxybutyrate) (P(3HB)). To release the monosaccharides, a diluted acid pre-treatment followed by an enzymatic hydrolysis was applied. A sugar yield of 49% was achieved using a pre-treated waste and an enzyme cocktail of Pentopan 500 BG and Celluclast BG. The addition of Glucoamylase NS 22035 helped to hydrolyze the starch fraction, improving the hydrolysis yield to 56%. The hydrolysate was used as culture medium to produce P(3HB) by Burkholderia sacchari DSM 17165. Assays at shaking flask scale showed that when the hydrolysate was used as substrate, the attained cell concentration was slightly higher than in the control medium. It was necessary to supplement the hydrolysate with extra glucose to increase the C/N ratio and with a mineral solution to overcome the nutritional deficiencies. The P(3HB) accumulation using the supplemented hydrolysate was 58% (g polymer/g biomass).