Characterization Of Distinct Enzymatic Saccharification Of Desirable Crop Straws Enhanced By Amaranthus Green Proteins Supply

Agricultural straws(potato,rice,wheat,rapeseed,corn),perennial crops(Amaranth,Miscanthus),and woody trees(poplar,Eucalyptus)provide abundant lignocellulose residues convertible for biofuels and value?added bioproducts.In particular,cellulosic ethanol has been considered as an outstanding additive to petrol fuels with less net carbon release.Plant cell walls are mainly composed of polysaccharides(cellulose,hemicelluloses,and pectin),lignin,and wall proteins,and lignocellulose recalcitrance is thus determined by plant cell wall composition,wall polymer feature,and wall network style.Due to lignocellulose recalcitrance,current bioethanol production requires an extremely biomass process such as strong physical and chemical pretreatments to disrupt lignocellulose,complete biomass enzymatic digestibility to release fermentable sugars,and durable yeast fermentation to achieve a high concentration of bioethanol.Despite several physical and chemical pretreatments that have been implemented to reduce lignocellulose recalcitrance,most technologies could simply cause costly biomass processing,and meanwhile,produce numerous toxic compounds that sequentially affect biomass enzymatic saccharification and finally inhibit yeast fermentation.Therefore,it becomes essential to find out a cost-effective and green-like strategy for efficient biomass enzymatic saccharification towards high bioethanol production.In this study,we initially collected the desirable lignocellulose substrates and then determined complete biomass saccharification to achieve the highest bioethanol yield in history by performing mild green-like pretreatments and co-supplying Amaranth proteins as active biosurfactant into enzymatic hydrolysis.Meanwhile,this study examined that the Amaranth proteins could act as effective biosorbent for multiple heavy/trace metals adsorption from agricultural soil.The major results were described below.In the first project,we conducted a classic colchicine treatment with diploidy(Dip)potato to generate tetraploid(Tet)and cytochimera(Cyt)potato samples.Compared to the Dip sample,both Tet and Cyt mature straws showed the biomass yields raised by 4 folds,total soluble sugars and starch levels increased by 2-4 folds.By performing two green-like pretreatments(liquid hot water/LHW,CaO),we examined that the Tet and Cyt straws were of remarkably enhanced biomass saccharification relative to the Dip,and particularly the Cyt straw showed complete saccharification with hexoses yield of 100%(% cellulose).Notably,two optimal pretreatments(8 min LHW at 200 °C;5% CaO at 50 °C)could cause complete enzymatic hydrolysis of soluble sugars,starch,and lignocellulose to maximize bioethanol yields of 23-24%(% dry matter)in the Cyt straw,which were higher than those of all other previouslymodified biomass residues even though had been performed under much stronger pretreatments.As a further comparison with Dip and Tet samples,the Cyt straw showed mostlessened lignocellulose recalcitrance such as reduced cellulose polymerization(DP)and lignin level,and raised cellulose accessibility and non-cellulosic polysaccharides deposition in both raw materials and pretreated lignocellulose residues.Hence,this study has proposed a novel mechanism model interpreting how the maximum bioethanol yields are achieved in the Cyt straw under two minimized green-like pretreatments,providing a powerful strategy for costeffective bioethanol production with minimum wastes release.In the second project,we detected that Amaranth plant was of rich lignocellulose residue(54 tons of dry matter per ha)applicable as ideal feedstock for bioethanol production,and also extracted more than 20% proteins from Amaranth green tissues.We then examined that the Amaranthus green proteins,which consist of distinct biological process enzymes and all human-essential amino acids,could enable to act as active biosurfactant at low dosages for universal enhancements of lignocellulose enzymatic hydrolyses by 12-105% upon mild and green-like pretreatments examined in eight grassy and woody bioenergy plants.Notably,while total green proteins of the Amaranth plants harvested from one-hectare land were supplemented into the lignocellulose enzymatic hydrolyses,it was estimated that additional6400-12400 tons of bioethanol would be obtained,being over 10-fold higher than those of soybean seed proteins supplements.Protein profiling and Western blot analyses demonstrated that the Amaranthus proteins could specifically interact with lignin to block its adsorption with cellulases for enhanced biomass enzymatic hydrolysis.In addition,this study examined three fractions of Amaranth raw straw grown in heavy metals-contaminated lands such as extractable proteins,solid lignocellulose residues,and soluble trace metals.As a comparison,the Amaranth proteins could act as a dominated biosorbent for multiple heavy metals(Cd,Pb,As)adsorption,being 3.3-,2.9-,and 6-folds higher than those of the lignocellulose residues.Importantly,this study characterized that the Amaranth proteins were effectively involved in diverse chemical bindings with Cd,interpreting why the Amaranth proteins could efficiently remove multiple heavy metals for plant remediation.Therefore,this study finally proposed a mechanism model highlighting how the Amaranth proteins,except the high quality of proteins additives into food and feed,could act as universal biosurfactant and biosorbent for enhanced lignocellulose enzymatic saccharification and heavy metal remediation.