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A Solvent-Free Approach for Production of Films from Pectin and Fungal Biomass

Gurram, Rajesh, Souza Filho, Pedro F., Taherzadeh, Mohammad J., Zamani, Akram
Journal of polymers and the environment 2018 v.26 no.11 pp. 4282-4292
Citrus, Rhizopus oryzae, compression molding, fungal biomass, fungi, glycerol, heat, lipid content, lipids, nutrients, pectins, permeability, protein content, proteins, scanning electron microscopy, tensile strength, wastes, water solubility, water vapor
Self-binding ability of the pectin molecules was used to produce pectin films using the compression molding technique, as an alternative method to the high energy-demanding and solvent-using casting technique. Moreover, incorporation of fungal biomass and its effects on the properties of the films was studied. Pectin powder plasticized with 30% glycerol was subjected to heat compression molding (120 °C, 1.33 MPa, 10 min) yielding pectin films with tensile strength and elongation at break of 15.7 MPa and 5.5%, respectively. The filamentous fungus Rhizopus oryzae was cultivated using the water-soluble nutrients obtained from citrus waste and yielded a biomass containing 31% proteins and 20% lipids. Comparatively, the same strain was cultivated in a semi-synthetic medium resulting in a biomass with higher protein (60%) and lower lipid content (10%). SEM images showed addition of biomass yielded films with less debris compared to the pectin films. Incorporation of the low protein content biomass up to 15% did not significantly reduce the mechanical strength of the pectin films. In contrast, addition of protein-rich biomass (up to 20%) enhanced the tensile strength of the films (16.1–19.3 MPa). Lastly, the fungal biomass reduced the water vapor permeability of the pectin films.