| Kaihua paper used to be court paper in Ming and Qing Dynasties.However,due to historical reasons,its production technology has been interrupted for more than a hundred years.At present,Kaihua County,Zhejiang Province attaches great importance to the restoration of the traditional process of Kaihua paper,and has organized a number of units to explore and study the traditional process of Kaihua paper.In this paper,the chemical characteristics,physical properties and mildew-proof mechanism were studied with the Wikstroemia bark as fiber raw material,which provided scientific and theoretical basis for the recovery,industrial development and resource utilization of Wikstroemia.In this paper,twice weak alkali cooking and bleaching process was used to prepare the pulp.Taking Mulberry bark and Broussonetia bark as control samples,the fiber length,width,functional groups,crystallinity and their changing rules were analyzed and tested by fiber analyzer,FT-IR and XRD.The results show that there are differences in fiber morphology among Mulberry bark,Broussonetia bark and Wikstroemia bark,but all of them are slender and have good uniformity and strength.Bleaching will reduce the length and width of pulp fiber,but the extent of decline is different.The length and width of Mulberry bark decrease greatly,23.9% and 12.0%.The length and width of the Wikstroemia bark decreased by 12.6% and 6.0% respectively.FT-IR and XRD show that there are more intermolecular hydrogen bonds in the pulp prepared by twice weak alkali cooking and bleaching process.In the process of pulping,the crystallinity will increase,and the crystallinity of Wikstroemia pulp is 60.8%,which is within the optimal range of 60～65%.There is a certain amount of Ca CO3 alkali reserves in Mulberry pulp and Wikstroemia pulp.Therefore,the comprehensive properties of the pulp prepared by the secondary weak alkali cooking and bleaching process are better than those of Mulberry bark and tissue pulp.Then,Wikstroemia paper was made by using twice weak alkali cooking and bleaching process,and the differences of paper properties made from different fiber raw materials were further studied with bagasse paper,Mulberry paper and Broussonetia paper as control samples.The results show that the whiteness performance of Broussonetia paper is better,indicating that the p H value of Mulberry paper is better,but the aging retention rate of the test index of Wikstroemia paper is high.After aging for 12 days,the whiteness and tensile index retention rates are 96.92% and 93.48%respectively.According to the calculation of polymerization degree,it takes 216 days for the paper to age completely,which is longer than Mulberry paper and Broussonetia paper and much longer than bagasse paper.The results of gel permeation chromatography showed that in the process of wet-heat aging,paper would produce more components with lower relative molecular weight,which would reduce the average molecular weight of cellulose and narrow the molecular weight distribution significantly.After aging for 12 days,the molecular weight distribution of Wikstroemia paper decreased by 44%,which was less than bagasse,Mulberry and Broussonetia paper.Then,the anti-mildew properties of Wikstroemia paper pulp were studied by extracting and analyzing the components and cultivating Trichoderma Wikstroemia.The results showed that the Wikstroemia pulp contains a variety of potentially mildew resistant and antibacterial components.Wikstroemia pulp extract can inhibit the growth of Trichoderma Reek Wikstroemia,causing the hypha to wither and shrink,and inhibiting the cellulase activity.In the end,through real-time fluorescence quantitative PCR technology and transcriptome sequencing analysis,the mildew-proof performance of Kaihua Wikstroemia paper was further explored at the gene level.The results showed that the expression of Env1,Cre1 and Xyr1 genes were all enhanced under the treatment of the extract of Wikstroemia pulp,and the expression of 123946 gene was slightly enhanced.Organisms have central regulatory factors to cope with stress for negative feedback regulation,so when survival is stressed by unfavorable factors,they will strengthen their expression on related genes to fight against unfavorable factors.In the treatment environment of extract,the distribution of Trichoderma reesei gene expression level widened,and the proportion of low-expression genes increased especially.A total of1662 genes with significant differences were identified,among which 861 genes were up-regulated and 801 genes were down-regulated.The gene expression of repeated samples was consistent,and the gene expression of the control group was quite different from that of the treatment group.According to KEGG annotation results,among the1090 differentially expressed genes of Trichoderma reesei,most of them are annotated in biological process category,and only a few are annotated in molecular function category.Regulation of cell biosynthesis of nucleic acid and protein;Cell assembly and macromolecular substance localization;Negative feedback and positive feedback of biological process;Stress response;There are significant differences in gene expression items such as endocytosis system,and there are many related genes.This result can be mutually confirmed by the analysis of RPKM expression distribution,which shows that the treatment of the extract from the pulp of Wikstroemia indica will have a significant impact on the related genes in the growth process of Trichoderma reesei.According to KEGG annotation results,there were 1722 differentially expressed genes in 245 metabolic pathways.It was found that the overall expression of metabolic regulation genes showed a downward trend,the expression of negative feedback regulation related genes showed an upward trend,and the overall expression of glucose metabolism related genes showed an upward trend.Compared with four genes(Env1,Cre1,Xyr1,123946)of real-time fluorescence PCR,the results are consistent.In conclusion,the paper made with Wikstroemia as raw material and cultured handmade paper technology has good durability and can inhibit the growth of Trichoderma Resteri by affecting gene expression and cellulase activity. |
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