• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1054-1063
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• 2022

Trehalose is a non-conventional sugar with potent applications in the food, healthcare and biopharma industries. In this study, trehalose was synthesized from maltose using whole-cell Pseudomonas monteilii TBRC 1196 producing trehalose synthase (TreS) as the biocatalyst. The reaction condition was optimized using 1% Triton X-100 permeabilized cells. According to our central composite design (CCD) experiment, the optimal process was achieved at 35℃ and pH 8.0 for 24 h, resulting in the maximum trehalose yield of 51.60 g/g after 12 h using an initial cell loading of 94 g/l. Scale-up production in a lab-scale bioreactor led to the final trehalose concentration of 51.91 g/l with a yield of 51.60 g/g and productivity of 4.37 g/l/h together with 8.24 g/l glucose as a byproduct. A one-pot process integrating trehalose production and byproduct bioremoval showed 53.35% trehalose yield from 107.4 g/l after 15 h by permeabilized P. moteilii cells. The residual maltose and glucose were subsequently removed by Saccharomyces cerevisiae TBRC 12153, resulting in trehalose recovery of 99.23% with 24.85 g/l ethanol obtained as a co-product. The present work provides an integrated alternative process for trehalose production from maltose syrup in bio-industry.

• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1455-1464
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• 2021

Trehalose is a non-reducing disaccharide in increasing demand for applications in food, nutraceutical, and pharmaceutical industries. Single-step trehalose production by trehalose synthase (TreS) using maltose as a starting material is a promising alternative process for industrial application due to its simplicity and cost advantage. Pseudomonas monteilii TBRC 1196 was identified using the developed screening method as a potent strain for TreS production. The TreS gene from P. monteilii TBRC 1196 was first cloned and expressed in Escherichia coli. Purified recombinant trehalose synthase (PmTreS) had a molecular weight of 76 kDa and showed optimal pH and temperature at 9.0 and 40℃, respectively. The enzyme exhibited >90% residual activity under mesophilic condition under a broad pH range of 7-10 for 6 h. Maximum trehalose yield by PmTreS was 68.1% with low yield of glucose (4%) as a byproduct under optimal conditions, equivalent to productivity of 4.5 g/l/h using enzyme loading of 2 mg/g substrate and high concentration maltose solution (100 g/l) in a lab-scale bioreactor. The enzyme represents a potent biocatalyst for energy-saving trehalose production with potential for inhibiting microbial contamination by alkaline condition.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.341-345
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• 2007

Fifty endophytic bacteria, which produced slime around the colonies, were isolated from Pueraria roots. In particular, HDN-14, TDG-3, and TNB-3 strains, which appeared to be high viscosity producers, were selected. These strains produced high levels of polysaccharides in Puerara root medium extract. The purified polysaccharide was digested with 1N HCI and analyzed by HPLC, with glucose ($45.6{\sim}63.1%$), maltose ($14.6{\sim}23.7%$), and fructose ($17.4{\sim}23.7%$) detected as constitutive sugars. When determined by the homology relationship of the 16S rDNA sequence with the relative taxa, the HDN-14 and TNB-3 strains were closely ($99.06{\sim}99.32%$) related to the Pseudomonas $koreensis^T$ and Pseudomonas $jessenii^T$, while TDG-3 were closely ($99.48{\sim}99.74%$) related to Pseudomonas $plecoglossicida^T$, Pseudomonas $mosselii^T$, and Pseudomonas $monteilii^T$. The major cellular Pseudomonas acids are $3OH-C_{10:0}$, $2OH-C_{12:0}$, $3OH-C_{12:0}$, and $3OH-C_{12:1}$, with these strains being further differentiated in species belonging to the genus Pseudomonas.

• Journal of Life Science
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• v.18 no.12
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• pp.1771-1774
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• 2008

Control microbial contamination in pathogens to soy sprouts has always been highly concerned in soybean sprout industries because the soybean sprouts are consumed largely as a nutritious fresh vegetable around the world. However, pathogens in soy sprouts are little known. Here, we isolated a strain of Pseudomonas sp. SN239 that caused severer symptoms in sprouts of many soybean cultivars. In phylogenetic relationships using 16S ribosomal RNA sequences of the Pseudomonas species, the identified Pseudomonas sp. SN239 was grouped with P. putita, P. plecoglossicida, P. monteilii and P. mevalonii. Thus, the bacterial strain SN239 might be a newly identified Pseudomonas species which closely related to P. putida. Furthermore, we found that a Korean indigenous soybean (Glycine max) cultivar YNPCSS3-19 has strong resistance against the Pseudomonas sp. SN239.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.410-419
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• 2018

It is urgently required to construct safety data on agricultural by-products imported for use as medium materials for domestic mushroom production. However, research on microorganisms is insufficient. This study was conducted to investigate the presence of bacteria that have the possibility of harmful effects on human, plants and mushroom in wheat straw, peatmoss, cottonseed hull, cottonseed meal, and beet pulp imported from Australia, Canada, China, Egypt, Germany. Bacteria were found in the range of $1.35{\times}10^2$ to $8.34{\times}10^6CFU/g$. As a result of 16S rDNA sequence analysis, total of 19 genera and 45 species of bacteria were identified. Bacillus genus was dominant, followed by Paenibacillus genus. At the species level, diverse species was in the order of Firmicute, Proteobacteria and Actinobacteria. Regarding the agricultural by-products, straw and peat moss had more diverse bacteria than other agricultural by-products. Among the indentified bacteria, 6 species of 5 genera (Enterobacter asburiae, Enterobacter ludwigii, Stenotrophomonas maltophilia, Pseudomonas monteilii, Bacillus anthracis, and Cellulosimicrobium funkei) were present as potent harmful bacteria to human. Surprisingly, both the human and plant pathogenic Klebsiella pneumoniae subsp. pneumonia was present. Bacillus altitudinis was present as a plant pathogen. Lysinibacillus sphaericus, an insect pathogen, and Ochrobactrum pseudogrignonense, a mushroom pathogen, were also present. The results of this study confirmed that several kinds of pathogenic bacteria were present in the agricultural by-products for the mushroom cultivation medium imported into Korea. Our work suggests that hygiene inspection and management is urgently needed for imported agricultural by-products to be safely used for mushroom production.