Phosphate solubilization and plant growth properties are promoted by a lactic acid bacterium in calcareous soil.

On the basis of good phosphate solubilization ability of a lactic acid bacteria (LAB) strain Limosilactobacillus sp. LF-17, bacterial agent was prepared and applied to calcareous soil to solubilize phosphate and promote the growth of maize seedlings in this study. A pot experiment showed that the plant growth indicators, phosphorus content, and related enzyme activity of the maize rhizospheric soils in the LF treatment (treated with LAB) were the highest compared with those of the JP treatment (treated with phosphate solubilizing bacteria, PSB) and the blank control (CK). The types of organic acids in maize rhizospheric soil were determined through LC-MS, and 12 acids were detected in all the treatments. The abundant microbes belonged to the genera of Lysobacter, Massilia, Methylbacillus, Brevundimonas, and Limosilactobacillus, and they were beneficial to dissolving phosphate or secreting growth-promoting phytohormones, which were obviously higher in the LF and JP treatments than in CK as analyzed by high-throughput metagenomic sequencing methods. In addition, the abundance values of several enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology, and Carbohydrate-Active Enzymes (CAZys), which were related to substrate assimilation and metabolism, were the highest in the LF treatment. Therefore, aside from phosphate-solubilizing microorganisms, LAB can be used as environmentally friendly crop growth promoters in agriculture and provide another viable option for microbial fertilizers. KEY POINTS: • The inoculation of LAB strain effectively promoted the growth and chlorophyll synthesis of maize seedlings. • The inoculation of LAB strain significantly increased the TP content of maize seedlings and the AP concentration of the rhizosphere soil. • The inoculation of LAB strain increased the abundances of the dominant beneficial functional microbes in the rhizosphere soil.

Flavobacterium lacisediminis sp. nov., a bacterium isolated from lake sediment.

A taxonomic identification using polyphasic approach was performed on strain TH16-21T, which was isolated from the interfacial sediment of Taihu Lake, PR China. Strain TH16-21T was Gram-stain-negative, aerobic, rod-shaped and catalase-positive. Phylogenetic analysis based on the 16S rRNA gene and genomic sequences indicated that strain TH16-21T was classified within the genus of Flavobacterium. The 16S rRNA gene sequence of strain TH16-21T showed the highest similarity to Flavobacterium cheniae NJ-26T (98.9 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain TH16-21T and F. cheniae NJ-26T were 91.2 and 45.9 %, respectively. The respiratory quinone was menaquinone 6. The major cellular fatty acids (>10 %) comprised iso-C15 : 0, iso-C16 : 0, iso-C15 : 1 G and iso-C16 : 0 3-OH. The genomic DNA G+C content was 32.2 mol%. Phosphatidylethanolamine, six amino lipids and three phospholipids were the main polar lipids. Based on the phenotypic features and phylogenetic position, a novel species with the name Flavobacterium lacisediminis sp. nov. is proposed. The type strain is TH16-21T (=MCCC 1K04592T=KACC 22896T).

Application of biochar in microbial fuel cells: Characteristic performances, electron-transfer mechanism, and environmental and economic assessments.

Biochar is a by-product of thermochemical conversion of biomass or other carbonaceous materials. Recently, it has garnered extensive attention for its high application potential in microbial fuel cell (MFC) systems owing to its high conductivity and low cost. However, the effects of biochar on MFC system performance have not been comprehensively reviewed, thereby necessitating the evaluation of the efficacy of biochar application in MFCs. In this review, biochar characteristics were outlined based on recent publications. Subsequently, various applications of biochar in the MFC systems and their probable processes were summarized. Finally, proposals for future applications of biochar in MFCs were explored along with its perspectives and an environmental evaluation in the context of a circular economy. The purpose of this review is to gain comprehensive insights into the application of biochar in the MFC systems, offering important viewpoints on the effective and steady utilization of biochar in MFCs for practical application.

Flavobacterium taihuense sp. nov., a bacterium isolated from lake sediment.

A novel bacterium, designated NAS39T, was isolated from the interfacial sediment of Taihu Lake in PR China and its taxonomic position was investigated by using a polyphasic approach. Cells of the isolate were Gram-stain-negative, aerobic, non-motile, catalase-positive, yellow and rod-shaped. Phylogenetic analyses based on 16S rRNA gene sequences supported that strain NAS39T formed a cluster within the genus Flavobacterium, and was most closely related to Flavobacterium laiguense LB2P30T (98.4 %), followed by Flavobacterium tiangeerense 0563T (97.4 %). The average nucleotide identity values between strain NAS39T and F. laiguense LB2P30T and F. tiangeerense 0563T were 82.5 and 75.3 %, respectively. The digital DNA-DNA hybridization values between strain NAS39T and F. laiguense LB2P30T and F. tiangeerense 0563T were 40.9 and 18.6 %, respectively. The genomic DNA G+C content was 34.1 mol%. The major respiratory quinone was menaquinone-6. The dominant cellular fatty acids were iso-C15 : 0 and summed feature 3 comprising C16 : 1 ω7c/C16 : 1 ω6c. The polar lipids comprised phosphatidyl ethanolamine, two amino lipids, three amino phospholipids and two unidentified lipids. Based on the phenotypic, chemotaxonomic, genotypic and phylogenetic characteristics, strain NAS39T (=MCCC 1K06094T=KACC 22328T) represents a novel species of the genus Flavobacterium, for which the name Flavobacterium taihuense sp. nov. is proposed.

Responses of microbial community and antibiotic resistance genes to co-existence of chloramphenicol and salinity.

In recent years, the risk from environmental pollution caused by chloramphenicol (CAP) has emerged as a serious concern worldwide, especially for the co-selection of antibiotic resistance microorganisms simultaneously exposed to CAP and salts. In this study, the multistage contact oxidation reactor (MCOR) was employed for the first time to treat the CAP wastewater under the co-existence of CAP (10-80 mg/L) and salinity (0-30 g/L NaCl). The CAP removal efficiency reached 91.7% under the co-existence of 30 mg/L CAP and 10 g/L NaCl in the influent, but it fluctuated around 60% with the increase of CAP concentration and salinity. Trichococcus and Lactococcus were the major contributors to the CAP and salinity shock loads. Furthermore, the elevated CAP and salinity selection pressures inhibited the spread of CAP efflux pump genes, including cmlA, tetC, and floR, and significantly affected the composition and abundance of antibiotic resistance genes (ARGs). As the potential hosts of CAP resistance genes, Acinetobacter, Enterococcus, and unclassified_d_Bacteria developed resistance against high osmotic pressure and antibiotic environment using the efflux pump mechanism. The results also revealed that shifting of potential host bacteria significantly contributed to the change in ARGs. Overall, the co-existence of CAP and salinity promoted the enrichment of core genera Trichococcus and Lactococcus; however, they inhibited the proliferation of ARGs. KEY POINTS: • Trichococcus and Lactococcus were the core bacteria related to CAP biodegradation • Co-existence of CAP and salinity inhibited proliferation of cmlA, tetC, and floR • The microorganism resisted the CAP using the efflux pump mechanism.

Dyadobacter flavalbus sp. nov., isolated from lake sediment.

A novel bacterial strain, designated NS28T, was isolated from interfacial sediment sampled at Taihu Lake, PR China. Cells were rod-shaped, Gram-negative, aerobic and non-motile on Reasoner's 2A medium. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NS28T was most closely related to species from the genus Dyadobacter, with 98.4 and 96.0 % 16S rRNA gene sequence similarity to its closest phylogenetic neighbours Dyadobacter sediminis CGMCC 1.12895T and Dyadobacter luticola CCTCC AB 2017091T, respectively. MK-7 was the only cellular menaquinone. The major fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0 and C16 : 1ω5c. The major polar lipids were phosphatidylethanolamine, one phospholipid, one aminolipid, one lipid and two unidentified lipids. Genomic analysis of strain NS28T indicated that the total genome size was 6 477 094 bp with a G+C content of 44.8 mol%, 5380 protein-coding genes, 79 contigs and an N50 length of 299584 bp. On the basis of the genomic DNA sequence, the average nucleotide identity values were 90.5 and 74.1 % with D. sediminis CGMCC 1.12895T and D. luticola CCTCC AB 2017091T, respectively. Digital DNA-DNA hybridization results of strain NS28T with D. sediminis CGMCC 1.12895T and D. luticola CCTCC AB 2017091T were 40.9 and 18.6 %, respectively. Based on the phenotypic, chemotaxonomic, phylogenetic and genome sequence data presented here, it is proposed that strain NS28T represents a novel species of the genus Dyadobacter for which the name Dyadobacter flavalbus is proposed . The type strain is NS28T (=NBRC 113854T=MCCC 1K03764T).

Gemmobacter caeruleus sp. nov., a novel species originating from lake sediment.

An aerobic, Gram-stain-negative, non-spore-forming and rod-shaped bacterial strain, designated N8T, was isolated from the interfacial sediment of Taihu Lake in PR China. The strain formed white to blue colonies on R2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain N8T represented a member of the genus Gemmobacter and was most closely related to Gemmobacter aquaticus A1-9T (97.97 %). The average nucleotide identity and digital DNA-DNAhybridization values between strain N8T and G. aquaticus A1-9T based on their whole genomes were 78.8 and 21.7 %, respectively. Q-10 was the main predominant ubiquinone. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C18 : 0 and C16 : 0. The G+C content of the genomic DNA was 66.1 mol%. The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid, two unidentified glycolipids and two unidentified lipids. Based on its physiological, biochemical and chemotaxonomic characteristics, strain N8T represents a novel species of the genus Gemmobacter, for which the name Gemmobacter caeruleus sp. nov. is proposed. The type strain is N8T=(KACC 21307T=MCCC 1K04036T).

Rufibacter hautae sp. nov., a red-pigmented bacterium from freshwater lake sediment, and proposal of Rufibacter quisquiliarum as a latter heterotypic synonym of Rufibacter ruber.

A taxonomic identification using a polyphasic approach was performed on strain NBS58-1T, which was isolated from the interfacial sediment of Taihu Lake in China. Strain NBS58-1T was Gram-stain-negative, aerobic, non-spore-forming and catalase-positive. Phylogenetic analyses based on 16S rRNA gene and three housekeeping genes (rpoB, gyrB and dnaK) sequences supported the position that strain NBS58-1T should be classified within the genus Rufibacter. The 16S rRNA gene sequence of strain NBS58-1T possessed the highest similarity to Rufibacter sediminis H-1T (96.60 %), followed by Rufibacter glacialis MDT1-10-3T (96.17 %). And the ANI value between strain NBS58-1T and R. glacialis MDT1-10-3T was 79.3 %. The respiratory quinone was menaquinone 7 (MK-7). The major cellular fatty acids comprised iso-C15 : 0 and summed feature 3. Phosphatidylethanolamine, two unidentified phospholipids and four unidentified lipids were the main polar lipids. The genomic DNA G+C content was 51.3 mol%. Based on phenotypic features and phylogenetic position, a novel species with the name Rufibacter hautae sp. nov. is proposed. The type strain is NBS58-1T=(KACC 21309T=MCCC 1K04037T). We also proposed Rufibacter quisquiliarum as a latter heterotypic synonym of Rufibacter ruber.

Agrococcus sediminis sp. nov., an actinobacterium isolated from lake sediment.

A novel strain, designated NS18T, was isolated from sediment sampled at Taihu Lake, PR China. Cells of the isolate were spherical, aerobic, non-motile, Gram-stain-positive and non-endospore-forming. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NS18T clustered in a clade of the genus Agrococcus. Its closest phylogenetic neighbour was Agrococcus lahaulensis DSM 17612T with 98.2 % 16S rRNA gene sequence similarity. The complete genome of NS18T was 2 736 037 bp and its genomic DNA G+C content was 72.8 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain NS18T and A. lahaulensis DSM 17612T based on their whole genomes were 85.1 and 28.7 %, respectively. The major fatty acids were anteiso-C17 : 0 and anteiso-C15 : 0. The predominant menaquinones were MK11 and MK12. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol and two unidentified lipids. The components of the peptidoglycan were Ala, Gly, Asp, Thr and DAB. The whole-cell sugars contained rhamnose, ribose, xylose and glucose. According to the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain NS18T (=NBRC 113859T=MCCC 1K03759T) represents a novel species, for which the name Agrococcus sediminis sp. nov is proposed.

Brevundimonas lutea sp. nov., isolated from lake sediment.

A novel Gram-negative, aerobic, rod-shaped bacterium, designated NS26T, was isolated from a sediment sample collected from Taihu Lake in China. Colonies were orange, circular, smooth and neat-edged on Reasoner's 2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NS26T belonged to the genus Brevundimonas and had the closest relationship with Brevundimonas halotolerans DSM 24448T (96.9 %). It grew at 20-37 °C (optimum, 28 °C), pH 5.5-10.5 (pH 7.0) and without NaCl. The major isoprenoid quinone was Q-10. The dominant cellular fatty acids were C18 : 1ω7c, C16 : 0 and C18 : 1ω7c 11-methyl. The polar lipid profile comprised 1,2-diacyl-3-O-(6-phosphatidyl-α-d-glucopyranosyl) glycerol, 1,2-di-O-acyl-3-O-α-d-glycopyranuronosyl glycerol, sulfoquinovosyl diacylglycerol, 1,2-di-O-acyl-3-O-[d-glycopyranosyl-(1→4)-α-d-glucopyranuronosyl] glycerol and phosphatidylglycerol. The G+C content of genomic DNA was 68.4 mol%. The average nucleotide identity value between strain NS26T and B.halotolerans DSM 24448T was 75.6 %. Based on the polyphasic taxonomic study, strain NS26T is suggested to be a novel species, for which the name Brevundimonas lutea sp. nov. is proposed. The type strain is NS26T (=CGMCC 1.13680T=NBRC 113554T).

Description of Ornithinibacillus gellani sp. nov., a halophilic bacterium isolated from lake sediment, and emended description of the genus Ornithinibacillus.

A Gram-stain-positive, strictly aerobic, motile and rod-shaped bacterium, designated strain LJ137T, was isolated from the sediment of Taihu Lake in China. A polyphasic approach was used to investigate its taxonomic position. Strain LJ137T grew optimally at pH 7.5, at 37 °C and with 2.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain LJ137T was most closely related to the genera Ornithinibacillus and Oceanobacillus. The closest phylogenetic neighbours were Ornithinibacillus halophilus KCTC 13822T, Ornithinibacillus salinisoli LCB256T and Oceanobacillus limi KCTC 13823T, with 95.2, 96.5 and 95.6 % 16S rRNA gene sequence similarity, respectively. The peptidoglycan amino acid type was A4α (l-Lys-d-Asp). The major respiratory quinone was menaquinone-7 (MK-7). The polar lipids of strain LJ137T contained diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids, two aminophospholipids and one unidentified lipid. The G+C content of the genomic DNA was 40.4 mol%. The dominant cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C15 : 0. Based on the phenotypic, chemotaxonomic, phylogenetic and genome sequence characteristics of this strain, a novel species, Ornithinibacillus gellani sp. nov., is proposed. The type strain is LJ137T (=CGMCC 1.13678T=NBRC 113552T). An emended description of the genus Ornithinibacillus is presented.

Rufibacter sediminis sp. nov., isolated from freshwater lake sediment.

A novel Gram-stain-negative, aerobic and rod-shaped bacterial strain, designated H-1T, was isolated from the interfacial sediment of Taihu Lake in China and characterized by using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the organism was most closely related to Rufibacter immobilis MCC P1T and Rufibacter tibetensis 1351T, with sequence similarities of 98.0 and 97.6 %, respectively. DNA-DNA relatedness between strain H-1T and R. immobilis MCC P1T and R. tibetensis 1351T was 48.8 and 36.6 %, respectively. The major (>5 %) cellular fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 1ω5c, iso-C15 : 0, summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) and anteiso-C15 : 0. The polar lipids comprised phosphatidylethanolamine, three unidentified aminophospholipids, an unidentified phospholipid and three unidentified lipids. The major respiratory quinone was menaquinone 7 (MK-7). Genomic DNA G+C content was 49.0 mol%. Based on its physiological, biochemical and chemotaxonomic characteristics, the strain represents a novel species of the genus Rufibacter, for which the name Rufibacter sediminis sp. nov. (type strain H-1T=CGMCC 1.16289T=NBRC 113030T) is proposed.

Altererythrobacter amylolyticus sp. nov., isolated from lake sediment.

An aerobic, motile, Gram-stain-negative bacterium, designated strain NS1T, was isolated from interfacial sediment from Taihu Lake, China. The strain formed yellow colonies on R2A medium. Cells were ovoid to rod-shaped and non-spore-forming. Growth occurred at 15-40 °C (optimum, 28 °C), at pH 5.0-10.5 (optimum, 6.5-7.5) and in the presence of 0-1 % (w/v) NaCl (optimum, 0 %). Phylogenetic trees based on 16S rRNA gene sequences showed that strain NS1T represented a member of the genus Altererythrobacter and had the highest sequence similarity to Altererythrobacter troitsensis CCTCC AB 2015180T (97.1 %). The average nucleotide identity value between strain NS1T and the closest related strain based on their genomes was 78.6 %. The predominant ubiquinone was Q-10. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid, an unidentified glycolipid and six unidentified lipids. The genomic DNA G+C content was 66.6 mol%. On the basis of phenotypic and genotypic characteristics, strain NS1T represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter amylolyticus sp. nov. is proposed. The type strain is NS1T (=CGMCC 1.13679T=NBRC 113553T).

A novel genus of the class Actinobacteria, Longivirga aurantiaca gen. nov., sp. nov., isolated from lake sediment.

A novel actinobacterial strain, designated X5T, was isolated from the sediment of Taihu Lake in China and was subjected to a polyphasic taxonomic characterization. The strain formed orange-red colonies comprising aerobic, Gram-stain-negative, rod-shaped cells on R2A agar. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the organism was closely related to the genus Sporichthya and consistently formed a distinct clade along with the members of this genus. The closest phylogenetic neighbour was Sporichthya polymorpha NBRC 12702T with 93.7 % 16S rRNA gene sequence similarity. The major fatty acids (>10 %) were iso-C16 : 0 (18.7 %), C18 : 1ω9c (18.6 %) and C17 : 1ω8c (14.0 %). The genomic DNA G+C content was 74.4 mol%. The organism contained menaquinone MK-8(H2), MK-9(H4) and an unidentified menaquinone. Polar lipids were composed of phosphatidylglycerol, an unidentified lipid, two unidentified phospholipids and two unidentified aminolipids. The whole-cell sugars contained ribose, xylose, mannose, glucose and galactose. The cell-wall peptidoglycan contained ll-diaminopimelic acid. Based on the physiological, biochemical and chemotaxonomic data, the organism is proposed to represent a novel genus and species, for which the name Longivirga aurantiaca gen. nov., sp. nov. is proposed. The type strain is X5T (=CGMCC 4.7317T=NBRC 112237T).

Nocardioides taihuensis sp. nov., isolated from fresh water lake sediment.

A novel actinobacterial strain, designated X17T, was isolated from the sediment of Taihu Lake in China and its taxonomic position was investigated by using a polyphasic approach. The isolate formed milky-white colonies comprising aerobic, Gram-stain-positive, rod-shaped cells. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the organism belonged to the genus Nocardioides and consistently formed a distinct cluster with Nocardioides agariphilus JCM 16020T and Nocardioides islandensis MSL 26T, sharing 95.5 and 94.8 % 16S rRNA gene sequence similarities, respectively. The genomic DNA G+C content was 69.9 mol%. Chemotaxonomically, the isolate contained ll-diaminopimelic acid in the cell-wall peptidoglycan, MK-8 (H4) as the predominant menaquinone, and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the polar lipids found in the cell wall. The major fatty acids were 18 : 1 ω9c (38.6 %), 16 : 0 iso (20.3 %), 15 : 0 iso (6.8 %) and 18 : 0 (5.8 %). Based on its physiological, biochemical and chemotaxonomic characteristics, the strain represents a novel species of the genus Nocardioides, for which the name Nocardioides taihuensis sp. nov. (type strain X17T=CGMCC 4.7318T=NBRC 112321T) is proposed.

A Novel Nanofilm Sensor Based on Poly-(Alizarin Red)/Fe3O4 Magnetic Nanoparticles-Multiwalled Carbon Nanotubes Composite Material for Determination of Nitrite.

Fe3O4 magnetic nanoparticles were synthesized by chemical co-precipitation with sodium citrate as surfactant and were characterized by FT-IR spectrometer, X-ray diffraction and transmission electron microscopy. A novel nitrite sensor was fabricated by electropolymerization of alizarin red on the surface of glassy carbon electrode modified with Fe3O4-multiwalled carbon nanotubes composite nanofilm. Under the optimal experimental conditions, it was showed that the proposed sensor exhibited good electrocatalytic activity to the oxidation of nitrite, and the peak current increased linearly with the nitrite concentration from 9.64 x 10(-6) mol x L(-1) to 1.30 x 10(-3) mol x L(-1) (R = 0.9976) with a detection limit of 1.19 x 10(-6) mol x L(-1) (S/N = 3). This sensor showed excellent sensitivity, wide linear range, stability and repeatability for nitrite determination with potential applications.

Improvement of the freezing resistance characteristics of yeast in dough starter.

Improving the freezing resistance of yeast in dough starters is one of the most effective methods to promote the healthy development of frozen dough technology. When the dough starter was composed of yeast, lactic acid bacteria and acetic acid bacteria, the microbial proportion was 10:1:5, and the ratio of wheat flour to corn flour was 1:1. The proline contents of the starters and the survival rates and fermentation capacity of yeast significantly increased compared with those of the starter composed of yeast and wheat flour only (P < 0.05). Laser confocal microscopy observation showed that the cell membrane damage of yeast obviously decreased. Low-field nuclear magnetic resonance method revealed that the water distribution state of starters changed. Adding corn flour and acetic acid bacteria to dough starter in appropriate proportions improves yeast freezing resistance.

Fermentation properties and functional stability of dough starter Jiaozi and Laomian after frozen storage.

Purpose: This study aims to investigate the effects of frozen storage on the stability of traditional dough starters in China. Methods: The microbial community structure and abundance of related metabolic genes in different fermented sourdough prepared by Jiaozi (JZ) and Laomian (LM) starters before and after frozen storage at -20°C for half a year were analyzed using the shotgun metagenomic sequencing method, and differences in characteristics of texture in steamed bread were also compared by formal methods. Results: The fermentation ability (FA) and metabolic activities of yeast in the JZH sourdough (started by JZ which was stored at -20°C for half a year) were better than those of LMH sourdough (started by LM which was stored at -20°C for half a year). The dominant genera of Acetobacter were found to be increased in the JZH0 sourdough (started by JZH and fermented for 0 h) and those of Lactobacillus were found to be decreased. Lactobacillus (98.72%), Pediococcus (0.37%), Saccharomyces (0.27%), and Acetobacter (0.01%), were dominant in sourdough LMH0 (started by LMH and fermented for 0 h). The abundances of "oxidative phosphorylation-related enzymes" and the "biosynthesis of glutamate"-related enzymes and genes related to "biosynthesis of glutamate" and "unsaturated fatty acid" were higher in JZH0 than in the JZ0 sourdough (started by JZ without being frozen and fermented for 0 h). The good FA of yeast, the acid production capacity of bacteria in the sourdough, and the quality of the JZH steamed bread (made by the JZH starter) indicated the better freezing tolerance of the microorganisms in JZ than in LM. Conclusion: The conclusion of this study suggests the better application potential of the JZ as the fermentation starter in actual production.

Geodermatophilus taihuensis sp. nov., isolated from the interfacial sediment of a eutrophic lake.

A novel actinobacterial strain, 3-wff-81(T), was isolated from interfacial sediment of the eutrophic Taihu Lake in Jiangsu Province (China) and subjected to polyphasic taxonomic characterization. The strain formed pale orange-pigmented colonies comprising rod-shaped cells on R2A agar. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain 3-wff-81(T) belonged to the genus Geodermatophilus, with Geodermatophilus soli PB34(T) (99.1 % similarity) and Geodermatophilus terrae PB261(T) (98.3 % similarity) as closest relatives. The major fatty acids were 16 : 0 iso, 15 : 0 iso, 17 : 1ω8c and 14 : 0 iso. The predominant menaquinones were MK-9(H4) and MK-9. Polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The genomic DNA G+C content was 73.2 mol%. DNA-DNA relatedness values with G. soli PB34(T) and G. terrae PB261(T) were 42.8 % and 39.6 %, respectively. Based on the physiological, biochemical and chemotaxonomic data, it is proposed that strain 3-wff-81(T) represents a novel species named Geodermatophilus taihuensis sp. nov. with 3-wff-81(T) ( = CGMCC 1.12303(T) = NBRC 109416(T)) as the type strain.

Characterization of a Novel One-Domain Halotolerant Laccase from Parageobacillus thermoglucosidasius and Its Application in Dye Decolorization.

Laccases are widespread multi-copper oxidases and generally classified into three-domain laccases and two-domain laccases. In this study, a novel laccase PthLac from Parageobacillus thermoglucosidasius harbored only one domain of Cu-oxidase_4 and showed no sequence relatedness or structure similarity to three-domain and two-domain laccases. PthLac was heterologously expressed in Escherichia coli, purified, and characterized. The optimum temperature and pH of PthLac on guaiacol were at 60 ℃ and pH 6, respectively. The effects of various metal ions on PthLac were analyzed. All the tested metal ions did not suppress the activity of PthLac, except for 10 mM Cu2+, which increased the activity of PthLac to 316%, indicating that PthLac was activated by Cu2+. Meanwhile, PthLac kept 121% and 69% activity when incubated at concentrations of 2.5 and 3 M NaCl for 9 h, suggesting the long-term halotolerancy of this enzyme. In addition, PthLac showed resistance to the organic solvents and surfactants, and displayed dye decolorization capacity. This study enriched our knowledge about one-domain laccase and its potential industrial applications.