The Research On The Production Of Cellulose Nanoparticles With Lignocellulose

With the rapid development of today's society,the demand of biochemical products and green materials.are increasing.Lignocellulose is the cheapest and most abundant renewable resource on earth.Using lignocellulose as a raw material,turning it into biochemical products has become a hot spot of concern.Cellulose Nanoparticles?CNs?are nanoscale celluloses prepared from natural cellulose.They have the characteristics of nanoparticles,good mechanical properties and are environmental-friendly and renewable,and thus have broad application prospects.Cellulose is an important component of lignocellulose.The cellulose can be converted to cellulose nanoparticles after treatment.In this study,we used a combination of acid hydrolysis,ultrasonication,and enzymatic hydrolysis to produce CNs with lignocellulose.CNs were characterized using nanometer particle size and Zeta potential analyzer,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,Fourier transform infrared spectroscopy?FT-IR?and X-ray diffraction.First of all,we explored the production of cellulose nanoparticles by acid hydrolysis combined with ultrasonication.The corn stover was pretreated with NaOH solution to remove lignin,followed by bleaching with sodium hypochlorite solution.The bleached corn stover is subjected to acid hydrolysis with 64%H₂SO₄ to produce CNs.The crystallinity was measured by an X-ray diffraction and observed by transmission electron microscope.The results showed that the crystallinity of CNs was higher than that of the original stover,and the length of CNs was about 180 nm and the width was about 50 nm.Secondly,this study also explored the combination of enzymatic hydrolysis and acid hydrolysis to produce CNs and glucose.The corn stover was enzymatically hydrolyzed by cellulase having an enzyme amount of 15 FPU/g cellulose and 25 FPU/g cellulose for 48h.The content of glucose was measured and the produced CNs were observed by transmission electron microscopy.The results showed that the enzymatic hydrolysis of 15FPU/g cellulose obtained the maximum yield of 9.37g/L of glucose at12h,and the enzymatic hydrolysis of 25FPU/g cellulose yielded the maximum yield of9.34g/L of glucose at 48h.The length of CNs obtained by acid hydrolysis after enzymatical hydrolysis for 48h were both between 100-300nm and the width was between 20-40nm.Simultaneous saccharification and fermentation?SSF?is a fermentation process that couples the enzymatic and fermentation processes together.In this study,NaOH-pretreated corn stover was used as substrates for simultaneous saccharification and fermentation to produce lactic acid.The yield of lactic acid reached a maximum of16.68 g/L at 72 h.After that,we studied feeding SSF.The results showed that the lactic acid of SSF supplemented with stover reached the maximum value of 15.01g/L in 84h.The lactic acid of SSF supplemented with enzyme and stover at the same time reached the maximum value of 16.88g/L in 48h.Using the method of SSF,the residues after fermentation was ultrasonicated,the crystallinity was measured by X-ray diffraction,and the produced CNs were observed by transmission electron microscopy.The CNs were prepared by ultrasonication of the residue after fermentation.The results showed that the crystallinity of CNs produced by ultrasonication after three kinds of SSF was improved compared with the original stover.The CNs prepared by ultrasonication after ordinary SSF were ellipsoidal,with a length of about 230 nm and a width of about 190nm.The CNs prepared by ultrasonication after SSF supplemented with stover or enzyme and stover are about 50 nm in width.The length is too long because of the agglomeration effect is long.