Nanocellulose (NC) from cellulosic biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. They still suffer, however, some drawbacks. The challenges are the exploration of raw materials, scaling, recovery of chemicals utilized for the production or functionalization and most important is toxic behavior that hinders them from implementing in medical/pharmaceutical field. This review emphasizes the structural behavior of cellulosic biomass and biological barriers for enzyme interactions, which are pertinent to understand the enzymatic hydrolysis of cellulose for the production of NCs. Additionally, the enzymatic catalysis for the modification of solid and NC is discussed. The utility of various classes of enzymes for introducing desired functional groups on the surface of NC has been further examined. Thereafter, a green mechanistic approach is applied for understanding at molecular level.

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Nanocellulose is an emerging sustainable biomaterial with exceptional physicochemical properties. It can be isolated from inexpensive renewable cellulosic biomass. Wood cellulose is the most extensively used biomass for the isolation of nanocellulose. Yet, owing to their hydrophilic nature, their utilization is restricted to applications involving hydrophilic or polar media, which limits their exploitation. With the presence of a large number of chemical functionalities within their structure, these building blocks provide a unique platform for significant surface modification through various methods. On the other hand, significantly used hazardous chemicals make the process environmentally unfriendly. Furthermore, recovery of used chemicals and toxicity of final products are the biggest challenges. To overcome these problems, the enzymatic approach is an emerging trend for isolation and surface modification of nanocellulose. This review assembles current knowledge in the research and development of nanocelluloses from cellulosic biomass and emphasizes the enzymatic routes developed so far for isolation, production, and functionalization.

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Functionally active membranes made of cellulosic microfibers (CMF) have emerged as promising sorbents for the removal of nano-sized pollutants from water. The adsorption efficiency of these membranes has been increased...

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Ultrasonic velocity and density values of l-phenylalanine, l-leucine, l-glutamic acid, and l-proline + 2 mol·L−1 aqueous NaCl and 2 mol·L−1 aqueous NaNO3 solutions have been measured for several molal concentrations of amino acids at different temperatures from T = (298.15 to 328.15) K. The isentropic compressibility values (κs) have been computed using the ultrasonic velocity and density data. The κs values decrease with an increase in the molal concentration of amino acids as well as with temperature. The trends of variation of κs with the variation in molal concentration of amino acids as well as with temperature have been discussed in terms of various interactions operative in solutions.

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