| Ramie is an Chinese characterictic textile fiber crop, its fiber is slender, flexible, strong, and with a silk-like sheen. Ramie fibers were entrapped in the matrix of polysaccharides such aspectin and hemicellulose, and the gums must be removed to liberate the fibers before spinning. Currently, bio-degumming is the most promising processing method for itslow pollutionhigh fiber quality, and low energy consumption. However, other biomass resource except fibers in the ramie bast or degumming liquors haven’t been noticed, recovered or utilized in the bio-degumming process so far. In the present study, ramie were degummed by microbial consortium RAMCD407, and the potential value of ramie biomass existed in the bio-degumming wastewater as well as ramie bast were surveyed, then the corresponding recovering and utilizing technology of flavone and enzymes were developed.The chemical analysis showed that the CODcr still as high as 8620mg/mL in the bio-degumming wastewater mainly constituted by proteins, saccharides, flavone, and terpene, etc, the content of them is 4.2g/L、0.6g/L、0.389% respectively. System test also display that the wastewater contains a little amount of the chemical constituents, such as phenols, organic acids and Terpenoids. The residual enzyme activity analysis suggested that the activity of the pectinase was the xylanase and the cellulase reached 3828U/mL, for activity reached 2708U/mL, and 381U/mL, respectively. So flavone and enzymes in the wastewater exhibited a high recovering and utilizing value.The level of flavone content in ramie bast was as high as 1.238%, to retrieve and utilize the flavone, two processes were studied and compared. One method was recovering flavones from the wastewater, however, only 0.413% of the total flavones can be obtained by this method due to the loss and the dilution in the process of bio-degumming; Moreover, the extracting agents were also difficult recycled in this process which would aggravate environment pollution. The other was extracting flavones form ramie bast in the pretreatment process of bio-degumming with ethanol-ultrasonic method. The optimum parameter was as follows: ramie bast was hammered with a rubber hammer before extracting, liquid-solid was 30:1, ethanol concentration 60%, ultrasound time was 40 min and extraction temperature was 30 ℃. The quantity of the flavonoids obtained by this method reached about 1.238% of the dry weight if the ramie phloem tested. Furthermore, it was found that the degumming time reduced by about 6 h and the COD ddecreaded to about 2835mg/mL in this process which confirmed that hammering combined with ethanol-ultrasonic treatment was also an effective pretreatment process for bio-degumming.Ultrafiltration Technology was used to recycle the enzymes from the ramie degumming wastewater. where 8KDa Super filter film and 0.08 MPa run pressure were selected. using this mentod, about 89.5% of the total protein can be recovered from the wastewater, including 85.04% of residual pectinase activities, 82.35% residual xynlase activities and 86.67% of residual cellulose activites. The enzymes obtained were reused for the ramie degumming experiments under the following conditions: incubation temperature 45 ℃, pH8.0, solid to liquor 1:10, enzyme concentration 30%(V/V), and the result show that fibers can be separated in 3h~4h, the residual gum of the final fibers was less than 9% and the overall quality were similar to those produced by commercial enzymes. |
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