An indole–3–acetic acid producing Bacillus altitudinis WR10 was previously isolated from the root of wheat (Triticum aestivum L.). In this study, the strain WR10 was used for relieving abiotic stresses in wheat under low phosphorus and high saline in hydroponic co-culture models. Significantly, strain WR10 improved wheat seed relative germination rate under salinity stress (200/400 mM NaCl) and the root dry weight in wheat seedlings under phosphorus stress (10 μM KH₂PO₃) when insoluble phosphates are available. To provide insights into its abiotic stress-alleviating properties, the strain was characterized further. WR10 grows well under different culture conditions. Particularly, WR10 resists salt (12% NaCl) and hydrolyzes both inorganic and organic insoluble phosphates. WR10 uses many plant-derived substrates as sole carbon and energy sources. It produces catalase, amylase, phosphatase, phytase, reductase, and 1–aminocyclopropane–1–carboxylate (ACC) deaminase. In addition, WR10 possesses long peritrichous flagella, and its biofilm formation, as well as phytase production, is induced by abiotic stresses. Overall, the salinity-alleviating property of WR10 in wheat can be attributed to its inherent tolerance to NaCl, formation of biofilm, and production of enzymes, like catalase, amylase, and ACC deaminase. Meanwhile, B. altitudinis WR10 reduces low-phosphorus stress in wheat by production of phosphatases and phytases in the presence of insoluble phosphates.

Genetic engineering of probiotics, like bifidobacteria, may improve their microbial cell factory economy. This work designed a novel shuttle plasmid pBPES, which bears exogenous appA and is stable within Bifidobacterium longum JCM 1217. Cloning of three predicted promoters into pBPES proved that all of them drive appA expression in B. longum JCM 1217. Transformation of plasmids pBPES-tu and pBPES-groEL into B. longum JCM1217 resulted in much more phytase secretion suggests P_tu and P_groEL are strong promoters. Further in vitro and in vivo experiments suggested B. longum JCM 1217/pBPES-tu degrades phytate efficiently. In conclusion, the study screened two stronger promoters and constructed a recombinant live probiotic strain for effectively phytase secretion and phytate degradation in gut. The strategy used in the study provided a novel technique for improving the bioaccessibility of phytate and decreasing phosphorus excretion.

A nonphotosynthetic, Gram-stain-negative, rod-shaped and motile strain, designated Pet-1T, was isolated from oil-contaminated soil collected from Daqing oil field in China. Optimal growth occurred at 37 °C, pH 5.5 and in 1 % (w/v) NaCl. Q-10 was the sole respiratory quinone. The most abundant fatty acid was C18 : 1ɷ7c/C18 : 1ɷ6c (67.4 %). The major polar lipids were phosphatidylglycerol, aminolipid, phosphatidylethanolaine, phosphatidycholine, two unidentified lipids and two unidentified phospholipids. The genomic DNA G+C content was 69.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that Pet-1T shared the highest similarity (95.1 %) to Rhodobacter vinaykumarii DSM 18714T, followed by Sinorhodobacter populi sk2b1T (95.0 %) and Haematobacter massiliensis CCUG 47968T (95.0 %). In the phylogenetic tree, strain Pet-1T formed a separate branch from the closely related genera Rhodobacter, Pararhodobacter, Defluviimonas and Rhodovulum within the family Rhodobacteraceae . Based on the data from the current polyphasic study, it is proposed that the isolate is a novel species of a novel genus within the family Rhodobacteraceae , with the name Solirhodobacter olei gen. nov., sp. nov. The type strain of the type species is Pet-1T (=KCTC 72074T =CCTCC AB 2018368T).

Quinoline is a typical nitrogen-heterocyclic compound with high toxicity and carcinogenicity which exists ubiquitously in industrial wastewater. In this study, a new quinoline-degrading bacterial strain Rhodococcus sp. JH145 was isolated from oil-contaminated soil. Strain JH145 could grow with quinoline as the sole carbon source. The optimum growth temperature, pH, and salt concentration were 30 °C, 8.0, and 1%, respectively. 100 mg/L quinoline could be completely removed within 28 h. Particularly, strain JH145 showed excellent quinoline biodegradation ability under a high-salt concentration of 7.5%. Two different quinoline degradation pathways, a typical 8-hydroxycoumarin pathway, and a unique anthranilate pathway were proposed based on the intermediates identified by liquid chromatography–time of flight mass spectrometry. Our present results provided new candidates for industrial application in quinoline-contaminated wastewater treatment even under high-salt conditions.