Isolation, Characterization, and Application of Nanocellulose from Agro-industrial By-products: A Review

Cellulose, consisting of β-anhydro-d-glucose units, is a natural, biodegradable, and versatile biopolymer with several applications in food and non-food systems. Cellulose is probably the most abundant biopolymer in the biosphere and is synthesized by multiple living organisms, ranging from some bacterial species to higher plants. Cellulose recovery was initially done from forest wood mainly. Other sources, including agro-industrial by-products, such as, fruit peels, husks, revealed to be potential reservoirs of cellulose. Recycling agro-industrial waste by recovering cellulose is an ideal strategy to mitigate the impact of food waste from agro-industrial activities. Moreover, the tremendous potential of cellulose nanomaterials has fueled researchers' interest in developing environmentally friendly extraction techniques. The present review paper focuses on the recovery of nanocellulose from different agro-industrial by-products and reports the advantages of the extraction technique used, such as, the use of deep eutectic solvents, ultrasound, steam explosion, mild acids, reduced effluents, amongst others. The importance of characterizing the physico-chemical properties of nanocellulose from different sources is also discussed. It is expected that scientific findings presented in this paper will highlight the potential of agro-industrial wastes as cellulose reservoirs and the importance of physico-chemical characterization of nanocellulose.