Strain YJY-8, a new γ-polyglutamic acid producer, was separated from fermented soybean paste samples. The strain was identified as a genus of Bacillus by morphological and 16S rDNA sequence analysis ...and was named Bacillus sp. YJY-8. The optimal medium composition and cultural conditions were studied using a single-factor experiment and a response surface experiment. The optimized medium consisted of monosodium glutamate 70 g/L, glucose 54.3 g/L, glycerol 31.8 g/L, ammonium sulfate 11.1 g/L, yeast extract 3.2 g/L, tryptone 1.5 g/L, L-glutamic acid 6.8 g/L, MgSO
4
7H
2
O 0.5 g/L, FeCl
3
6H
2
O 0.02 g/L, KH
2
PO
4
0.9 g/L, CaCl
2
0.03 g/L, MnSO
4
H
2
O 0.3 g/L, ammonium molybdate 0.02 g/L, pH 7.0. The optimal cultivation conditions were 35 °C and pH 7.0. Under the optimized conditions, after 48 hr of cultivation, the highest shaking flask fermentation level of γ-PGA reached 65.2 ± 0.36 g/L. In addition, through fed-batch fermentation in 30 L fermenters, the fermentation level of γ-PGA reached its highest level at 88.42 g/L and productivity was 1.23 g/(L hr) after 72 hr. Then, the effect of γ-PGA on tomato yield was investigated. At the seedling stage, the plant height and stem diameter of γ-PGA treated plants increased by 5.69 and 15.735% after spraying γ-PGA for 19 days. During the flowering and fruiting period, the stem diameter of the γ-PGA treatment group increased by 6.74%, with a maximum increase of 11.65%. The number of fruit branches increased by 0.56-16.29% and the number of fruit sets increased by 1.01-28.47%. At the fruit maturation stage, the yield of tomatoes increased by 10.51, 14.27, and 5.83%.
In this study, a high protease-producing strain was screened by spread plate method and identified by molecular biology and morphological identification. It was identified as Bacillus sp. LCB14. A ...neutral protease gene was cloned and heterologous expressed by B. subtilis SCK6. Then, the recombinant protease was used to dehair the goat skins. The fermentation conditions of neutral protease production by B. subtilis SCK6 were optimized. The single factor experiments, Plackett-Burma experiment, and response surface method were conducted to determine fermentation medium and culture conditions. The optimized medium contained corn meal 49 g/L, soluble starch 28 g/L, soybean meal 17 g/L, corn steep liquor powder 8 g/L, yeast extract 10 g/L, Na
2
HPO
4
2.3 g/L, KH
2
PO
4
1.9 g/L, MgSO
4
0.5 g/L, MnCl
2
0.1 g/L and ZnSO
4
0.05 g/L. The optimized culture conditions were 35 °C and pH 7.0. Under the optimum conditions, the recombinant strain reached 33467.28 U/mL after 72 hr ferment. Moreover, by fed batch in 30 L fermenters, neutral protease production reached 39,440.78 U/mL and shortened fermentation time from 72 hr to 46 hr. Finally, the crude enzyme was utilized to replace sodium sulfide for dehairing of goatskins. The enzymatic dehaired pelts were white, smooth, and soft; the grain side of enzymatic dehaired pelts were clear; there was no obvious damage to the grain side of enzymatic dehaired pelts by visual observation and tactile test. Furthermore, there were no hair roots, hair follicles and other glands in enzymatic dehaired belts, and the collagen fibers of enzymatic dehaired belt were dispersed well by histological analysis.
We isolated a moderately halophilic lipase-producing bacterium from the saline soil. Based on the morphological, physiological, chemotaxonomic and phylogenetic analysis, the isolate PT-11 was ...postulated to be a novel species identified as Oceanobacillus rekensis PT-11. The lipase was purified 2.50-fold by Q-Sepharose FF and SP-Sepharose FF chromatography and its molecular mass was estimated to be 23.5 kDa by SDS-PAGE. It was highly active over the broad temperature ranging from 10 to 35°C and showed up to 80% of the maximum activity at 10°C indicating the lipase to be a typical cold-adapted enzyme. The enzyme activity was slightly enhanced by Na+, Li+ and K+. Incubation with detergents, such as Tween-20 and Tween-80, slightly inhibited the enzyme activity; while Triton X-100decreased the enzyme activity. The enzyme was fairly stable in the presence of long-chain alcohols but was highly denatured in hydrophilic solvents such as acetone or short-chain alcohols (C1-C3).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Resveratrol (1) undergoes microbial transformation when fermented with Streptomyces sp. A12 to yield 3, 5, 4′-trimethoxy-trans-stilbene (2). The structure of the compound 2 was elucidated using the ...modern spectroscopic techniques. This is the first report of the microbial transformation of resveratrol to compound 2 using the endophyte isolated from Polygonum cuspidatum.
A Gram-stain-positive, rod-shaped, aerobic, non-motile, non-sporulating bacterial strain, designated CSA1
T
, was isolated from chromium-containing soil sampled at a chemical plant. Growth of strain ...CSA1
T
occurred at pH 6–10 (optimum, pH 7), 15–45 °C (optimum, 30 °C) and in the presence of 0.5–6.5 % (w/v) NaCl (optimum, 2 %). The 16S rRNA gene sequence of strain CSA1
T
revealed the highest similarity to
Leucobacter ruminantium
A2
T
(97.5 %),
Leucobacter tardus
K 70/01
T
(97.3 %),
Leucobacter humi
Re6
T
(96.6 %),
Leucobacter kyeonggiensis
F3-P9
T
(96.2 %),
Leucobacter zeae
CC-MF41
T
(96.1 %) and
Leucobacter weissii
S27
T
(96.0 %). The draft genome of CSA1
T
was approximately 3 350 931 bp in size with a G+C content of 70.6 mol%. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values among strain CSA1
T
and the selected
Leucobacter
species were 74.0–79.2 % (ANIb), 84.3–87.1 % (ANIm) and 21.5–25.4 % (dDDH), which are below the recommended cutoff values for species delineation. The major fatty acids were anteiso-C
15 : 0
, iso-C
16 : 0
and anteiso-C
17 : 0
. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unknown glycolipid. The predominant menaquinones were MK-11, MK-8 and MK-6. The cell-wall amino acids were 2,4-diaminobutyric acid, alanine, glycine, glutamic acid and threonine. From the phenotypic, chemotaxonomic and molecular features, strain CSA1
T
was considered to represent a novel species of the genus
Leucobacter
, for which the name
Leucobacter chromiisoli
sp. nov. is proposed. The type strain is CSA1
T
(=JCM 34359
T
=CGMCC 1.18746
T
).
A moderately halophilic bacterium, strain HNA-14T, was isolated from a saline-alkali soil sample collected in Shache County, Xinjiang Province. On the basis of the polyphasic taxonomic data, the ...isolate was considered to be a member of the genus Bacillus. The organism grew optimally at 30°C and pH 8.0. It was moderately halophilic and its optimum growth occurred at 5−10% NaCl. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid and the predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0 and the polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and two unknown phospholipids. The G+C content of the genomic DNA was 48.6 mol%. Strain HNA-14T exhibited a low 16S rRNA gene sequence similarity of 96% with its nearest neighbors Bacillus clausii KSM-K16 (96.5%), Bacillus xiaoxiensis DSM 21943T(96.2%), Bacillus clausii DSM 8716T (96.1%), Bacillus patagoniensis PAT05T (96.1%), Bacillus lehensis MLB-2T (96.0%), Bacillus oshimensis K11T (95.9%) and Bacillus hunanensis DSM 23008T (95.8%) and the phenotypic characteristics indicate that strain HNA-14T can be distinguished from them. Therefore, a novel species of the genus Bacillus, Bacillus shacheensis sp. nov. (type strain, HNA-14T=KCTC 33145=DSM 26902) is proposed.
In this study, an extracellular metalloprotease (EMPr) from Bacillus sp. LCB14 was cloned, successfully expressed in Bacillus subtilis SCK6, and utilized to dehair goat skins in leather-making ...processes. Through optimization of fermentation conditions, the expression level of EMPr reached 6973 U/mL after 72 h of incubation. Then the crude enzyme was purified 6.30 fold through a three-step purification process of centrifugation, dialysis and SP Sepharose Fast Flow. The purified protease EMPr was established by 12.5% SDS-PAGE and showed 40.08 kDa. It exhibited highest activity 77,302 U/mg at pH 6.5 and 50 °C respectively. Protease activity was slightly enhanced by Li+ and K+. Interestingly, the protease activity was enhanced by the surfactants, such as, Tween 20, Tween 80, SDS, and Triton X-100 respectively. The dehairing experiments showed that the crude EMPr completely dehaired goatskins during 6 h at 33–35 °C without use of sodium sulfide. The enzymatic dehaired belt showed well opening up of fiber structure and the collagen was not damaged. Therefore the protease EMPr displayed great potential application in dehairing process without using sodium sulfide.
•A metalloprotease gene was cloned and highly expressed by Bacillus subtilis SCK6.•The goatskin was completely dehaired by EMPr without use of sodium sulfide at 33–35 °C.•The enzymatic dehaired belt showed better overall appearance and better whiteness.
Keratinase has a great commercial value owing to its applications in the enzymatic dehairing of goatskins. In this study, we adopted a combined strategy to enhance the extracellular recombinant ...keratinase activity in
SCK6. First, nine signal peptides were screened to enhance the expression of extracellular keratinase. The recombinant strain with SP
exhibited the highest extracellular keratinase activity of 739.03 U per mL, which was two-fold higher activity of the wild type. Second, based on the multiple sequence alignment with the bacterial alkaline proteases, the mutant (M123L/V149I/A242N) was introduced into the keratinase. Comparing with the wild type of keratinase, the mutant M123L/V149I/A242N showed an increase in the extracellular keratinase activity, which was about 1.2-fold higher activity of the wild type. Finally, the keratinase expression vector with SP
and mutant M123L/V149I/A242N was constructed, and the extracellular keratinase activity reported at 830.91 U per mL was a 2.2-fold activity of the wild type. Then, the mutant keratinase was purified and characterized. The mutant exhibited properties similar to those of the wild type at an optimal temperature of 60 °C and pH 10.0. Conclusively, the extracellular expression of keratinase was enhanced
a combined strategy, and the mutant keratinase demonstrated properties similar to that of the wild type of keratinase.
A novel streptomyces trypsin GM2938 was selected as the object of study. The active GM2938 contains 223 amino acid residues. Constructing recombinant plasmid and transforming Bacillus subtilis SCK6, ...the heterogenous expression of GM2938 was achieved. Through optimization of fermentation conditions, the expression level of GM2938 reached 1622.2 U/mL (esterase activity) and 33.8 U/mL (amidase activity). The recombinant trypsin was purified and measured: the specific activity of esterase was 5.6 × 103 U/mg, and the specific activity of amidase was 1.1 × 103 U/mg. Furthermore, the enzymatic properties of GM2938 were explore: the optimal reaction temperature and pH were 50 °C and 9.0, respectively; the recombinant enzyme show high stability at 25 °C and range of pH 5.0–9.0; Ca2+, K+, Mg2+, EDTA, DTT, DMSO, methanol, glycerin and ethanediol could promote the esterase and amidase activities at the investigated concentrations, while Fe2+, SDS, tritonx-100, acetone, chloroform and n-hexane inhibited the trypsin activities. Kinetic parameters of GM2938 were calculated: the Km of BAEE was 3.15 × 10−5 mol·L−1, Vmax value was 2.87 × 10−4 mol·L−1·min−1; the Km of BAPAN was 2.20 × 10−4 mol·L−1, the Vmax was 2.40 × 10−4 mol·L−1·min−1. These properties give trypsin GM2938 a potential application prospect.
An extracellular keratinase gene from Bacillus sp. LCB12, isolated from saline-alkali soil, was cloned and high-effectively expressed in Bacillus subtilis SCK6. The enzyme was purified by ammonium ...sulphate precipitation and cation-exchange chromatography. Its molecular mass was estimated to be 30.95 kDa by SDS-PAGE. The optimum conditions for catalytic activity of the enzyme were pH 10.0 and 60 °C. The enzyme activity was completely inhibited by PMSF, while it was slightly inhibited by EDTA. Moreover, the surfactants Tween 20, Tween 80 and Triton X-100, showed little effect on enzyme activity respectively. The crude enzyme was used as an alternative to sodium sulfide for dehairing of goat skins. The goatskin was dehaired by the enzyme at 33–35 °C in 6 h. The enzymatic dehaired pelt showed better general appearance and better whiteness by visual tests, and the grain surface of enzymatic dehaired pelt revealed absence of hair shaft with empty follicles by stereoscopic observation. Meanwhile, the epidermis was completely removed and the collagen fiber structure of enzymatic dehaired pelt was more opened, regular and even in dermis comparing with conventional dehaired pelt by histological analysis.
•A keratinase gene was cloned and highly expressed by Bacillus subtilis SCK6.•The goatskin was completely dehaired by keratinase without use of sodium sulfide at 33–35 °C.•The enzymatic dehaired belt showed better overall appearance and better whiteness.•The keratinase showed great potential application in leather industry.
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