There is a great interest in increasing the levels of production of nanocellulose, either by adjusting production systems or by improving the raw material. Despite all the advantages and applications, nanocellulose still has a high cost compared to common fibers and to reverse this scenario the development of new, cheaper, and more efficient means of production is required. The market trend is to have an increase in the mass production of nanocellulose; there is a great expectation of world trade. In this sense, research in this sector is on the rise, because once the cost is not an obstacle to production, this material will have more and more market. Production of the cellulose fibers is determinant for the production of nanocellulose by a hydrolyzing agent with a reasonable yield. This work presents several aspects of this new material, mainly addressing the enzymatic pathway, presenting the hydrolysis conditions such as pH, biomass concentration, enzymatic loading, temperature, and time. Also, the commonly used characterization methods are presented, as well as aspects of the nanocellulose production market.

A model is proposed to describe the growth and b-Galactosidase production by Kluyveromyces marxianus. It shows good agreement with the experimental data over a range of conditions. It also reliably predicts the effect of growth rate on the productivity of the protein. The simplicity and accuracy of the model make it suitable for designing and implementing control and optimization strategies for the production of protein at large scale.

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-Biosensors based on nanomaterial composites have been investigated for their potential to function as high sensitivity signal response devices. In the present study, we report the fabrication of silver nanoparticles (AgNPs) on a graphite epoxy composite electrode (GEC) and mixed with the polyaniline (a conductive emeraldine salt form polymer) composite electrode (AgNPs/PANI/GEC), in order to compare the performance of the generated electrochemical response signals. Cyclic voltammetry tests were conducted to compare the quality and intensity of signals from the different prepared electrodes. Tests for the AgNPs/PANI/GEC electrodes were made with and without the enzymes alcohol oxidase and horseradish peroxidase immobilized on the composite surface. The prepared AgNPs/PANI/GEC nanocomposite was evaluated by thermal analysis. Scanning electron microscopy images and EDX were obtained for characterization of the electrode surface morphology. Square wave voltammetry techniques were then employed for ethanol analysis with the AOX/HRP/AgNPs/PANI/GEC biosensor achieving good results in a range of 0.37M to 0.65 M.

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