Screening,Diversity And Function Analysis Of Bacteria For Ramie Bio-degumming

The pollution caused by the traditional chemical degumming is a bottleneck for the ramie processing industry.Efficient bio-degumming with microorganisms is of priority to solve the pollution problem.The aim of the study is to select high-efficient microbial strains for bio-degumming of ramie from various habitats.Besides,putative diversity analysis,degumming assessment,species identification were also carried out in the study.The conclusions of the paper are as follows:1.A total of 101 ramie degumming bacteria were enriched and screened from the particular habitats,which had the ability to have raw ramie degumed.At least 33 species distributed among 3phylums,5 classes,17 genuses were identified by sequence analysis of 16 S rRNA combinedwith morphological characteristics,of which56.44% were Bacillus.All the related sequences were submitted to the GenBank database.It is worth noting that PF50 X had the lowest homology as the query sequence blasted to the nucleotide database.2.The diversity indexesand and the uniform distributionof the culturable microorganisms for ramie degumming for artificial manure was relatively loweramong the habitats including soil,humic substances,feces and artificial manure,while the enhanced degree of dominant specieswas prominent though the functional strains were not abundant.The diversity indexesof the culturable microorganisms for ramie degumming for humic substances was the highest,meaning humic substances were more suitable for bio-degumming strains screening.3.The bio-degumming capability of the 101 strains was evaluated with ramie degumming.The strainsPF06 X,PF21X,PF28 X,PF32X,PF38 X,PF46X,PF56 Q,PF60Q and PF96 Q could have raw ramie degummed in 36 h.Transparent zone test revealed thestrains could secret enzymes related to deguming.PF21 X could had xylan and mannan hydrolyzed in short time,which could be regarded as an efficient ramiedegumming strain,but further study was needed.4.Compared with EC 01,an efficient degumming bacterium,the logarithmic phase of PF21 X was fairly delayed.By detecting the degumming effect and comparing the enzyme activity of xylanase and mannanase produced during fermentation,the capacity of xylanase production ofPF21 Xwas relatively big.Morphological observation of the degummed fibers with SEMcertified that PF21 X had ramie well degummed.The fibers degummed with PF21 Xwere completely dispersed and not obviously damaged,and the gum in the ramie wasbasically removed.But the residue gum was higher than that in the fibers degummed with DC 01.The residue gum in the fibers degummed with PF21 X for 24 h was6.51%,which is near the requirements for production practices.5.Attempt toidentify the related functional-coding genes as phylogenetic markers for PF21 X and a suspected new species PF50 X failed.Five pairs of universal primers of different sections of 16 S rRNAwere used to acquire effective results,the consequence of F3R3 primers were chosen as much more reliable selective sequencing after nr database comparison analysis in NCBI.After deeperhomology alignments between the top Lysinibacillus sinduriensis and L.xylanilyticus,PF21 X was close to L.xylanilyticus(KC708560.1).PF50 X had higher consistency with an uncultured bacterium LN564249.1 and Sphingobacterium sp.(JQ514560.1).Physiological and biochemical indexestest indicated PF21 X was consistent with those of L.xylanilyticus,and those of PF50 X were roughly the same as the general characteristicsof Sphingobacterium.Nevertheless,this species had the distinctive competences of gelatin hydrolysis.To sum up,PF21 X could be classified as L.xylanilyticus,and PF50 X as an untitled novel species in Sphingobacterium.