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A novel facultatively aerobic bacterium designated SY8 was isolated from a peanut rhizosphere soil sample collected in Jiangsu Province, China. Cells are Gram-stain-positive, rod-shaped, and agar colonies are creamy, opaque, and usually rhizoidal. Strain growth occurs at 30 - 45 °C (optimum 30 °C), pH 4.0 - 10.0 (optimum pH 6.0) and 0 - 4% (w/v) NaCl (optimum 2%) in Luria-Bertani medium. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strain SY8 forms a distinct lineage in the clade of genus Bacillus and is related to Bacillus pseudomycoides DSM 12442  T (99.9%). Phylogenetic analysis of the concatenated gene sequences of 16S rRNA, gryB and rpoD also indicated that strain SY8 forms a distinct lineage in Bacillus. Calculation of the average nucleotide identities and the digital DNA-DNA hybridization values between strain SY8 and the related type Bacillus strains further revealed that strain SY8 represents a distinct species. The predominant cellular fatty acids are iso C 15:0 (28.7%) and summed feature 3 (C 16:1 ω7c and/or C 16:1 ω6c) (10.3%). The major polar lipids consisted of diphosphatidyl glycerol, phosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidylinositol, and three unidentified phospholipids. The major menaquinone of SY8 was MK-7. Based on phenotypic, phylogenetic, chemotaxonomic, and genomic features, strain SY8 represents a novel species of the genus Bacillus. The name Bacillus arachidis sp. nov. is proposed with strain SY8 T (= CCTCC AB 2021100  T =LMG 32409  T ) designated as the type strain., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In recent years, there have been many studies on producing acetoin by microbial fermentation, while only a few studies have focused on chiral acetoin biosynthesis. The weight assignment method was first applied to balance the chiral purity (expressed as the enantiomeric excess value) and the titer of acetoin. Bacillus sp. H-18W, a thermophile, was selected from seven Bacillus strains for chiral acetoin production. To lower the cost of the fermentation medium, soybean meal was used as a feedstock. Four kinds of frequently used commercial proteinases with different active sites were tested for the hydrolyzation of the soybean meal, and the combination of the acidic proteinase and the neutral proteinase showed the best results. In a fermentation medium containing 100 g L -1 glucose and 200 g L -1 hydrolysate, Bacillus sp. H-18W produced 21.84 g L -1 acetoin with an ee value of 96.25% at 60 h. This is the first report of using a thermophilic strain to produce chiral acetoin by microbial fermentation. Thermophilic fermentation can reduce the risk of bacterial contamination and can save cooling water. Using soybean meal hydrolysate and glucose as feedstocks, this work provides an economical and alternative method for the production of chiral pure acetoin.

Lactones are useful flavor compounds and some 5-hydroxy-γ-butyrolactones also have important biological activities. In this study, a newly isolated Bacillus strain 1s-1 was identified to be capable of producing 5-hydroxy-γ-decalactone (HDL) from peanut oil by gas chromatography-mass spectrometry and authentic standards. The complete genome of this strain was sequenced and de novo assembled to a single circular chromosome of 4,166,290 bp with a guanine-cytosine content of 46.3%. The biosynthesis pathway of HDL in strain 1s-1 was postulated and this study provides helpful information for further utilizing Bacillus sp. 1s-1 as a source of valuable hydroxy lactones., (Copyright © 2018. Published by Elsevier B.V.)

Acyloins are useful organic compounds with reactive adjacent hydroxyl group and carbonyl group. Current research is usually constrained to acetoin (i.e. 3-hydroxy-2-butanone) and the biological production of other acyloins was scarcely reported. In this study, two hydroxy-pentanone metabolites (3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone) of Bacillus sp. H15-1 were identified by gas chromatography-mass spectrometry and authentic standards. Then the complete genome of this strain was sequenced and de novo assembled to a single circular chromosome of 4,162,101bp with a guanine-cytosine content of 46.3%, but no special genes were found for the biosynthesis of the hydroxy-pentanones. Since hydroxy-pentanones are the homologues of acetoin, the two genes alsD and alsS (encoding α-acetolactate decarboxylase and α-acetolactate synthase, respectively) responsible for acetoin formation in this strain were respectively expressed in Escherichia coli. The purified enzymes were found to be capable of transforming pyruvate and 2-oxobutanoate to the two hydroxy-pentanones. This study extends the knowledge on the biosynthesis of acyloins and provides helpful information for further utilizing Bacillus sp. H15-1 as a source of valuable acyloins., (Copyright © 2017 Elsevier B.V. All rights reserved.)

During 2,3,5,6-tetramethylpyrazine production from glucose by Bacillus strains, a novel product was detected and identified as 2,4,5-trimethylimidazole (TMI) by GC/MS. TMI appeared in the culture medium only after glucose had been depleted and then increased to 0.25-0.31 g l(-1) in 90-120 h. When the ammonium source was changed from (NH(4))(2)SO(4) to (NH(4))(2)HPO(4), only about one tenth of TMI was detected. Although the mechanistic events largely remain unclear, both microbial strains tested demonstrated similar dynamic processes of TMI production, suggesting that TMI formation is a genuine feature of Bacillus species.

Background: Most low molecular diols are highly water-soluble, hygroscopic, and reactive with many organic compounds. In the past decades, microbial research to produce diols, e.g. 1,3-propanediol and 2,3-butanediol, were considerably expanded due to their versatile usages especially in polymer synthesis and as possible alternatives to fossil based feedstocks from the bioconversion of renewable natural resources. This study aimed to provide a new way for bacterial production of an acetylated diol, i.e. acetylbutanediol (ABD, 3,4-dihydroxy-3-methylpentan-2-one), by acetoin metabolism., Methodology/principal Findings: When Bacillus pumilus ATCC 14884 was aerobically cultured in a chemically defined medium with acetoin as the sole carbon and energy source, ABD was produced and identified by gas chromatography--chemical ionization mass spectrometry and NMR spectroscopy., Conclusions/significance: Although the key enzyme leading to ABD from acetoin has not been identified yet at this stage, this study proposed a new metabolic pathawy to produce ABD in vivo from using renewable resources--in this case acetoin, which could be reproduced from glucose in this study--making it the first facility in the world to prepare this new bio-based diol product.

BACKGROUND Acetoin is an important biorefinery platform chemical with many industrial uses. It is mainly produced by chemical synthesis or mesophilic fermentation with high costs. RESULTS A thermophilic Bacillus strain was isolated to efficiently produce acetoin from maize hydrolysate at 50°C. The fermentation medium was statistically optimized by Plackett-Burman design. Operational conditions were then optimized using a 4.2 L fermenter conducted at 50°C without sterilization. Oxygen enriched air (65% oxygen) accelerated substrate consumption but did not increase product titer. In comparison with 600 rpm, agitation speed controlled at 400 rpm yielded less acetoin but more 2,3-butanediol in the final products. A two-stage pH control strategy (pH first at 6.6-7.1 then at 7.7-8.0) was applied to further increase the yield of acetoin. Finally, 50.8 g L-1 of acetoin and 32.1 g L-1 of 2,3-butanediol were obtained from 251 g L-1 of degermed maize flour (dry weight). The conversion yield from sugar to the 4-carbon compounds (acetoin and 2,3-butanediol) was 94.4% of the theoretical value. CONCLUSION This is the first report of non-sterilized fermentative production of acetoin. Using degermed maize hydrolysate as the main feedstock, this work sets a new titer record of acetoin fermentation among known thermophilic producing systems. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]