Biodiversity Of Culturable Bacteria Isolated From The Air Samples From A Liquor Fermentation Workshop In Jiugui Liquor Co. Ltd., China

In this study,the culturable bacteria in the air samples from a liquor fermentation workshop in Jiugui Liquor Co.Ltd.,China,were isolated by using the natural precipitation method and culture-dependent method.Then the bacteria diversity of the isolates was investigated by means of phylogenetic analysis based on 16S rRNA gene sequence comparisons.Then,the ability of the isolates to produe exoenzymes was studied by using some conventional methods.Furthermore,the polyphasic taxonomic approach was employed to establish the precise taxonomic positions of potential new taxa.According to their morphology and the results of some physiological and biochemical experiment,73 represented strains out of 127 isolates were selected to perform the phylogenetic analysis based on 16S rRNA gene sequences.The results demonstrated that the strains belonged to 24 genera?Acinetobacter,Agrococcus,Arsenicicoccus,Arthrobacter,Aurantimonas,Bacillus,Corynebacterium,Deinococcus,Exiguobacterium,Janibacter,Kocuria,Luteococcus,Microbacterium,Micrococcus,Paracoccus,Pararhodobacter,Pseudomonas,Rhodococcus,Shinella,Sphingomonas,Sporosarcina,Staphylococcus,Virgibacillus,Xanthomonas?of 16 families?Aurantimonadaceae,Bacillaceae,Bacillales,Corynebacteriaceae,Deinococcaceae,Intrasporangiaceae,Microbacteriaceae,Moraxellaceae,Nocardiaceae,Planococcaceae,Propionibacteriaceae,Pseudomonadaceae,Rhizobiaceae,Rhodobacteraceae,Sphingomonadaceae,Xanthomonadaceae?in 4 major phylogenetic groups?phylum??Actinobacteria,Deinococcus-Thermus,Firmicutes,Proteobacteria?.The most abundant and diverse isolates were within the phylum Actinobacteria?34 strains,46.58%?,followed by the phyla Proteobacteria?24 strains,32.89%?and Firmicutes?12 strains,16.44%?.The other 3 strains were members of the Deinococcus-Thermus phylogenetic group.The 73 represented strains could be classified as 54 genomic species,and the majority of strains,to some extent,exhibited genetic discrepancy with their relatives?96.37%–99.88%sequence similarity?.At least 5 strains?JSM 2215019,JSM 2215034,JSM 2215039,JSM 2215042 and JSM 2215109?should represent potential new species of the genera Arthrobacter,Corynebacterium,Deinococcus,Paracoccus and Sphingomonas.The ability of the iaolates to produe exoenzymes was studied by using some conventional methods,and the results showed that 59 out of 73?80.82%?strains tested cold produce at least one enzyme among the four exoenzymes observed?amylase,esterase,gelatinase,urease?,in which 26 strains could only produce one,and 19,10 and4 strains produced 2,3 and 4 exoenzymes,respectively.Then,the phylogenetic diversity of some positive strains was analysised based on 16S rRNA gene sequences.The results showed that:i)9 strains?JSM 2215002,JSM 2215012,JSM 2215017,JSM2215018,JSM2215076,JSM 2215104,JSM 2215109,JSM 2215126,JSM 2215134?could relatively strongly produce amylase,being members of 7 families?Bacillaceae,Deinococcaceae,Microbacteriaceae,Micrococcaceae,Nocardiaceae,Rhodobacteraceae,Xanthomonadaceae?in four phyla?Actinobacteria,Deinococcus-Thermus,Firmicutes,Proteobacteria?;ii)9 strains?JSM 2215018,JSM 2215021,JSM 2215027,JSM2215104,JSM 2215109,JSM 2215116,JSM 2215117,JSM 2215126,JSM 2215132?could relatively strongly produce hydrolase,belonging to 8 families?Bacillaceae,Deinococcaceae,Microbacteriaceae,Micrococcaceae,Moraxellaceae,Nocardiaceae,Rhodobacteraceae,Xanthomonadaceae?infourphyla?Actinobacteria,Deinococcus-Thermus,Firmicutes,Proteobacteria?;iii)7 strains?JSM 2215002,JSM2215040,JSM 2215076,JSM 2215095,JSM 2215104,JSM 2215109,JSM 2215134?could relatively strongly produce gelatinase,belonging to 5 families?Bacillaceae,Deinococcaceae,Rhodobacteraceae,Staphylococcaceae,Xanthomonadaceae?in three phyla?Deinococcus-Thermus,Firmicutes,Proteobacteria?;iv)6 strains?JSM 2215012,JSM 2215028,JSM 2215062,JSM 2215081,JSM 2215106,JSM 2215109?could relatively strongly produce urease,belonging to 5 families?Deinococcaceae,Micrococcaceae,Rhodobacteraceae,Shinella,Staphylococcaceae?in four phyla?Actinobacteria,Deinococcus-Thermus,Firmicutes,Proteobacteria?.The precise taxonomic position of an actinobacteria strain JSM 2215039 was investigated by using a polyphasic taxonomic approach.The results indicated that strain JSM 2215039 was a non-sporulating,non-motile,catalase-positive,oxidase-negative,aerobic,Gram-positive bacterium,exhibiting a rod-coccus growth cycle and producing a yellow pigment,being able to grow at 5–35°C?optimum 25–30°C?and pH 5.0–10.0?optimum pH 7.0?.The peptidoglycan type was A3??Lys-Ser-Thr-Ala?.Cell-wall sugars contained glucose and galatose.Possessing MK-9?H₂?as the major menaquinone,and diphosphatidylglycerol,phosphatidylglycerol and phosphatidylinositol as the major polar lipids,and anteiso-C_15:0 and iso-C_15:0 as the major cellular fatty acids.The DNA G+C content of strain JSM 2215039 was 66.9 mol%.Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JSM 2215039 should be a member of the genus Arthrobacter,being related most closely to the type strain of Arthrobacter agilis?sequence similarity 98.7%?,and the two strains formed a distinct lineage in the phylogenetic tree?Bootstrap value,100%?.The level of DNA–DNA relatedness between strain JSM 2215039 and the type strain of Arthrobacter agilis was 30.6%.The combination of phylogenetic analysis,DNA-DNA relatedness,phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 2215039represents a novel species of the genus Arthrobacter,for which the name Arthrobacter aerolatum sp.nov.is proposed.The type strain is JSM 2215039^T.In conclusion,the results showed that there is abundant bacterial diversity and some potential new taxa in the air samples from a liquor fermentation workshop in Jiugui Liquor Co.Ltd.,and that most of the strains isolated can produce exoenzymes?amylase,esterase,gelatinase and/or urease?.