Valorization of Passion Fruit Stalk by the Preparation of Cellulose Nanofibers and Immobilization of Trypsin

Abstract

Fibers from passion fruit stalks were first recovered with a pulping and bleaching process. Two mechanical treatments were further applied to the fibers, homogenization (with and without ultrasound), and blender application. The effect of those treatments on fibers was evaluated. The chemical composition of the different stages of fibers undergoing treatment were measured according to TAPPI standards and were also analyzed by SEM, FTIR, and XRD. Trypsin was immobilized by adsorption and by covalent binding. The biocatalyst support-trypsin was evaluated in terms of immobilization yield, retention, and enzymatic activity. The experimental results demonstrated that the final cellulose concentration in the fibers was 44 % higher than that in the raw stalks. The cellulose nanofibers obtained by homogenization presented a size distribution between 20-200 nm, and the application of ultrasound did not show a significant effect on size (between 50 to 300 nm). Trypsin immobilized using glycidol presented an immobilization yield of 67 % and presented higher retention and enzymatic activity (1.17±0.05 U/mg protein and 44.0±2.0 %, respectively). These results show that passion fruit stalks can be successfully used as a source of cellulose nanofibers and also can be used as carriers for the immobilization of trypsin.

Expression of Exogenous GFP-CesA6 in Tobacco Enhances Cell Wall Biosynthesis and Biomass Production

“…Probably, three different CesA isoforms take part to the synthesis of cellulose in the primary or secondary cell wall. In Arabidopsis , CesA1, CesA3, and CesA6-like groups (CesA2, CesA5, CesA6, and CesA9) are involved in primary cell wall growth, whereas the deposition of the secondary cell wall cellulose seems to be coordinated by the CesA4, CesA7, and CesA8 isoforms [ 3 , 4 , 5 ]. For a long time, cellulose microfibril was assumed to contain 36 β-1,4 glucan chains, supporting the CSC model in which each of the six subunits of the rosette contains six CesAs [ 6 , 7 , 8 , 9 ].…”