Ramie fiber is known as the “king of natural fibers,” and the key to its wide application is efficient and green manufacturing. Microbial degumming has gradually become a hot area of research due to its environmental protection and mild operating conditions. However, some gummy materials remain after microbial degumming. Xylan is the main component of residual gums; its acetylated branched chains create the space barrier that makes the removal of hemicellulose difficult during ramie degumming. An acetyl xylan esterase (AXE) was obtained from Bacillus pumilus and characterized to solve this problem. Its optimum temperature and pH were 35°C and 8.0, respectively, and it had good temperature and pH stability. These properties were consistent with the conditions of ramie degumming and they laid a foundation for the application of AXE in ramie degumming. Besides, an engineered strain with a high activity of AXE was constructed successfully on the basis of the wild-type degumming strain Pectobacterium carotovorum HG-49 and used for ramie degumming. The removal rate of hemicellulose and total gums by the engineered strain increased by 4.89% and 2.53%, respectively, compared with that of the wild-type strain. Moreover, the role of this AXE in ramie degumming was further proven by X-ray diffraction and scanning electron microscopy. This study showed that AXE played an important role in the removal of hemicellulose in the degumming process of ramie fibers, thus providing a promising degumming strategy for ramie and other bast fiber plants.
LiuLJChenHQDaiXB, et al.
Effect of planting density and fertilizer application on fiber yield of ramie (Boehmeria nivea). J Integr Agr2012;
11: 1199–1206.
2.
NiJLZhuAGWangXF, et al.
Genetic diversity and population structure of ramie (Boehmeria nivea L.). Ind Crop Prod2018;
115: 340–347.
3.
CaoJWZhengLSChenSY.Screening of pectinase producer from alkalophilic bacteria and study on its potential application in degumming of ramie. Enzyme Microb Technol1992;
14: 1013–1016.
4.
BruhlmannFLeupinMErismannKH, et al. Enzymatic degumming of ramie bast fibers. J Biotechnol2000;
76: 43–50.
5.
GuoFFZouMYLiXZ, et al.
An effective degumming enzyme from Bacillus sp. Y1 and synergistic action of hydrogen peroxide and protease on enzymatic degumming of ramie fibers. Biomed Res Int2013;
2013: 1–9.
6.
FanXSLiuZWLiuZT, et al.
A novel chemical degumming process for ramie bast fiber. Text Res J2010;
80: 2046–2051.
7.
AngeliniLGScalabrelliMTavariniS, et al.
Ramie fibers in a comparison between chemical and microbiological retting proposed for application in biocomposites. Ind Crop Prod2015;
75: 178–184.
8.
YangQDuanSWChengLF, et al. An effective degumming technology for ramie fibers based on microbial coculture strategy. J Nat Fibers2020; 1–11. DOI:10.1080/15440478.2020.1784819
9.
MukhopadhyayADuttaNChattopadhyayD, et al.
Degumming of ramie fiber and the production of reducing sugars from waste peels using nanoparticle supplemented pectate lyase. Bioresour Technol2013;
137: 202–208.
10.
LiuZCDuanSWSunQX, et al.
A rapid process of ramie bio-degumming by Pectobacterium sp. CXJZU-120. Text Res J2012;
82: 1553–1559.
11.
ZhengLSDuYMZhangJY.Degumming of ramie fibers by alkalophilic bacteria and their polysaccharide-degrading enzymes. Bioresour Technol2001;
78: 89–94.
12.
YangQDuanSWChengLF, et al.
Engineering of a Bacillus subtilis strain deficient in cellulase: application in degumming of ramie. Fiber Polym2019;
20: 57–62.
13.
ShuTBaiYWangYW, et al.
A high-efficiency and eco-friendly degumming process for ramie fibers. J Clean Prod2020;
276: 124217.
14.
FanPHeFYangY, et al.
In-situ microbial degumming technology with Bacillus sp. HG-28 for industrial production of ramie fibers. Biochem Eng J2015;
97: 50–58.
15.
Basu S, Saha MN, Chattopadhyay D, et al. Large-scale degumming of ramie fibre using a newly isolated Bacillus pumilus DKS1 with high pectate lyase activity. J Ind Microbiol Biotechnol 2009; 36: 239–245.
16.
MaoKWChenHGQiHH, et al.
Visual degumming process of ramie fiber using a microbial consortium RAMCD407. Cellulose2019;
26: 3513–3528.
17.
WangYBaiYShuT, et al.
Characterization of a versatile glycoside hydrolase Cel5M from Pectobacterium carotovorum HG-49 for ramie degumming. Text Res J2020;
90: 1602–1615.
HuyNDThiyagarajanSKimD, et al.
Cloning and characterization of a novel bifunctional acetyl xylan esterase with carbohydrate binding module from Phanerochaete chrysosporium. J Biosci Bioeng2013;
115: 507–513.
26.
ChessonAGordonAHLomaxJA.Substituent groups linked by alkali-labile bonds to arabinose and xylose residues of legume, grass and cereal straw cell walls and their fate during digestion by rumen microorganisms. J Sci Food Agric1983;
34: 1330–1340.
27.
DupontCDaigneaultNShareckF, et al.
Purification and characterization of an acetyl xylan esterase produced by Streptomyces lividans. Biochem J1996;
319: 881–886.
28.
KrastanovaIGuarnacciaCZaharievS, et al.
Heterologous expression, purification, crystallization, X-ray analysis and phasing of the acetyl xylan esterase from Bacillus pumilus. Biochim Biophys Acta2005;
1748: 222–230.
PouvreauLJonathanMCKabelMA, et al.
Characterization and mode of action of two acetyl xylan esterases from Chrysosporium lucknowense C1 active towards acetylated xylans. Enzyme Microb Technol2011;
49: 312–320.
31.
KwonMSongJParkH, et al.
Characterization of heterologously expressed acetyl xylan esterase1 isolated from the anaerobic rumen fungus Neocallimastix frontalis PMA02. Asian Australas J Anim Sci2016;
29: 1576–1584.
32.
WangQChenHGFangG, et al.
Isolation of Bacillus cereus P05 and Pseudomonas sp. X12 and their application in the ramie retting. Ind Crop Prod2017;
97: 518–524.
33.
BiasiniMBienertSWaterhouseA, et al.
SWISSMODEL: modelling protein tertiary and quaternary structure using evolutionary information. Nucleic Acids Res2014;
42: 252–258.
34.
TrottOOlsonAJ.AutoDock Vina: improving the speed and accuracy of docking with a new scoring function, efficient optimization, and multithreading. J Comput Chem2009;
31: 455–461.
35.
MillerGL.Use of dinitrosaiicyiic acid reagent for determination of reducing sugar. Anal Chem1959;
31: 426–428.
36.
GB/T 5882-1986:1986. Testing method of bundle breaking tenacity of ramie fiber.
37.
SegalLCreelyJJMartinAE, et al.
An empirical method for estimating the degree of crystallinity of native cellulose using the X-Ray diffractometer. Text Res J1959;
29: 786–794.
38.
AdesioyeFAMakhalanyaneTPBielyP, et al.
Phylogeny, classification and metagenomic bioprospecting of microbial acetyl xylan esterases. Enzyme Microb Technol2016; 93–94: 79–91.
39.
AdesioyeFAMakhalanyaneTPVikramS, et al.
Structural characterization and directed evolution of a novel acetyl xylan esterase reveals thermostability determinants of the carbohydrate esterase 7 family. Appl Environ Microb2018;
84: 8.
40.
Degrassi, G, M. Kojic, Goran Ljubijankic, et al. The acetyl xylan esterase of Bacillus pumilus belongs to a family of esterases with broad substrate specificity. Microbiology 2000; 146: 1585–1591.
41.
VincentFCharnockSJVerschuerenKHG, et al.
Multifunctional xylooligosaccharide/cephalosporin C deacetylase revealed by the hexameric structure of the Bacillus subtilis enzyme at 1.9Å resolution. J Mol Biol2003;
330: 593–606.
42.
Montoro-GarcíaSGil-OrtizFGarcía-CarmonaF, et al.
The crystal structure of the cephalosporin deacetylating enzyme acetyl xylan esterase bound to paraoxon explains the low sensitivity of this serine hydrolase to organophosphate inactivation. Biochem J2011;
436: 321–330.
43.
EminoğluAÜlkerSSandallıC.Cloning, purification and characterization of acetyl xylan esterase from Anoxybacillus flavithermus DSM 2641T with activity on low molecular-weight acetates. Protein J2015;
34: 237–242.
44.
WuHLXueYLiHL, et al. Heterologous expression of a new acetyl xylan esterase from Aspergillus niger BE-2 and its synergistic action with xylan-degrading enzymes in the hydrolysis of bamboo biomass. BioResources2016;
12: 434–447.
45.
LiHLXueYWuJL, et al.
Enzymatic hydrolysis of hemicelluloses from Miscanthus to monosaccharides or xylo-oligosaccharides by recombinant hemicellulases. Ind Crop Prod2016;
79: 170–179.
46.
LiabKAzadiPCollinsR, et al.
Relationships between activities of xylanases and xylan structures. Enzyme Microb Technol2000;
27: 89–94.
47.
TianQQSongPJiangL, et al.
A novel cephalosporin deacetylating acetyl xylan esterase from Bacillus subtilis with high activity toward cephalosporin C and 7-aminocephalosporanic acid. Appl Microbiol Biot2014;
98: 2081–2089.
48.
JuturuVAustCWuJC.Heterologous expression and biochemical characterization of acetyl xylan esterase from Coprinopsis cinerea. World J Microbiol Biotechnol2013;
29: 597–605.
49.
WangYWShuTFanP, et al.
Characterization of a recombinant alkaline thermostable β-mannanase and its application in eco-friendly ramie degumming. Process Biochem2017;
61: 73–79.
50.
YangYZhuNYangJS, et al.
A novel bifunctional acetyl xylan esterase/arabinofuranosidase from Penicillium chrysogenum P33 enhances enzymatic hydrolysis of lignocellulose. Microb Cell Fact2017;
16: 1.
51.
LiZFLiZLDingRY, et al. Composition of ramie hemicelluloses and effect of polysaccharides on fiber properties. Text Res J2015;
86: 451–460.
52.
XiangMXBaiYLiYR, et al.
An eco-friendly degumming process of flax roving without acid pickling and NaClO2-bleaching. Process Biochem2020;
93: 77–84.
53.
SistiLTotaroGVanniniM, et al.
Evaluation of the retting process as a pre-treatment of vegetable fibers for the preparation of high-performance polymer biocomposites. Ind Crop Prod2016;
81: 56–65.
