scholarly journals Microbial 2-butanol production with Lactobacillus diolivorans

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Hannes Russmayer ◽  
Hans Marx ◽  
Michael Sauer
Keyword(s):  
Cell Factory ◽  
Butanol Production ◽  
Wild Type ◽  
Bacterial Strains ◽  
Butanol Tolerance ◽  
Bulk Chemicals ◽  
Cultivation Process ◽  
Key Driver ◽  
First Time ◽  
Efficient Producer

Abstract Background Biobutanol has great potential as biofuel of the future. However, only a few organisms have the natural ability to produce butanol. Amongst them, Clostridium spp. are the most efficient producers. The high toxicity of biobutanol constitutes one of the bottlenecks within the biobutanol production process which often suffers from low final butanol concentrations and yields. Butanol tolerance is a key driver for process optimisation and, therefore, in the search for alternative butanol production hosts. Many Lactobacillus species show a remarkable tolerance to solvents and some Lactobacillus spp. are known to naturally produce 2-butanol from meso-2,3-butanediol (meso-2,3-BTD) during anaerobic sugar fermentations. Lactobacillus diolivorans showed already to be highly efficient in the production of other bulk chemicals using a simple two-step metabolic pathway. Exactly, the same pathway enables this cell factory for 2-butanol production. Results Due to the inability of L. diolivorans to produce meso-2,3-BTD, a two-step cultivation processes with Serratia marcescens has been developed. S. marcescens is a very efficient producer of meso-2,3-BTD from glucose. The process yielded a butanol concentration of 10 g/L relying on wild-type bacterial strains. A further improvement of the maximum butanol titer was achieved using an engineered L. diolivorans strain overexpressing the endogenous alcohol dehydrogenase pduQ. The two-step cultivation process based on the engineered strain led to a maximum 2-butanol titer of 13.4 g/L, which is an increase of 34%. Conclusion In this study, L. diolivorans is for the first time described as a good natural producer for 2-butanol from meso-2,3-butanediol. Through the application of a two-step cultivation process with S. marcescens, 2-butanol can be produced from glucose in a one-vessel, two-step microbial process.

scholarly journals Engineering a Cyanobacterial Cell Factory for Production of Lactic Acid

2012 ◽  
Vol 78 (19) ◽  
pp. 7098-7106 ◽  
Author(s):  
S. Andreas Angermayr ◽  
Michal Paszota ◽  
Klaas J. Hellingwerf
Keyword(s):  
Lactic Acid ◽  
Lactate Dehydrogenase ◽  
Lactic Acid Production ◽  
Lactate Production ◽  
Cell Factory ◽  
Wild Type ◽  
Extracellular Medium ◽  
Content Type ◽  
Bulk Chemicals ◽  
Versatile Tool

ABSTRACTMetabolic engineering of microorganisms has become a versatile tool to facilitate production of bulk chemicals, fuels, etc. Accordingly, CO2has been exploited via cyanobacterial metabolism as a sustainable carbon source of biofuel and bioplastic precursors. Here we extended these observations by showing that integration of anldhgene fromBacillus subtilis(encoding anl-lactate dehydrogenase) into the genome ofSynechocystissp. strain PCC6803 leads tol-lactic acid production, a phenotype which is shown to be stable for prolonged batch culturing. Coexpression of a heterologous soluble transhydrogenase leads to an even higher lactate production rate and yield (lactic acid accumulating up to a several-millimolar concentration in the extracellular medium) than those for the singleldhmutant. The expression of a transhydrogenase alone, however, appears to be harmful to the cells, and a mutant carrying such a gene is rapidly outcompeted by a revertant(s) with a wild-type growth phenotype. Furthermore, our results indicate that the introduction of a lactate dehydrogenase rescues this phenotype by preventing the reversion.

scholarly journals Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Christine Landlinger ◽  
Lenka Tisakova ◽  
Vera Oberbauer ◽  
Timo Schwebs ◽  
Abbas Muhammad ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Bactericidal Activity ◽  
High Selectivity ◽  
Ex Vivo ◽  
Vaginal Microbiome ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Promising Alternative ◽  
First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

scholarly journals Bark traits, decomposition and flammability of Australian forest trees

2017 ◽  
Vol 65 (4) ◽  
pp. 327 ◽  
Author(s):  
Saskia Grootemaat ◽  
Ian J. Wright ◽  
Peter M. van Bodegom ◽  
Johannes H. C. Cornelissen ◽  
Veronica Shaw
Keyword(s):  
Forest Tree ◽  
Remarkable Feature ◽  
Interspecific Differences ◽  
Eucalypt Plantations ◽  
Physical Traits ◽  
Key Driver ◽  
Multiple Species ◽  
Species Specific ◽  
First Time ◽  
Different Tissues

Bark shedding is a remarkable feature of Australian trees, yet relatively little is known about interspecific differences in bark decomposability and flammability, or what chemical or physical traits drive variation in these properties. We measured the decomposition rate and flammability (ignitibility, sustainability and combustibility) of bark from 10 common forest tree species, and quantified correlations with potentially important traits. We compared our findings to those for leaf litter, asking whether the same traits drive flammability and decomposition in different tissues, and whether process rates are correlated across tissue types. Considerable variation in bark decomposability and flammability was found both within and across species. Bark decomposed more slowly than leaves, but in both tissues lignin concentration was a key driver. Bark took longer to ignite than leaves, and had longer mass-specific flame durations. Variation in flammability parameters was driven by different traits in the different tissues. Decomposability and flammability were each unrelated, when comparing between the different tissue types. For example, species with fast-decomposing leaves did not necessarily have fast-decomposing bark. For the first time, we show how patterns of variation in decomposability and flammability of bark diverge across multiple species. By taking species-specific bark traits into consideration there is potential to make better estimates of wildfire risks and carbon loss dynamics. This can lead to better informed management decisions for Australian forests, and eucalypt plantations, worldwide.

scholarly journals Seed morphology uncovers 1500 years of vine agrobiodiversity before the advent of the Champagne wine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vincent Bonhomme ◽  
Jean-Frédéric Terral ◽  
Véronique Zech-Matterne ◽  
Sarah Ivorra ◽  
Thierry Lacombe ◽  
...  
Keyword(s):  
Middle Ages ◽  
Climatic Changes ◽  
Seed Morphology ◽  
Crucial Aspect ◽  
Wild Type ◽  
Grape Seeds ◽  
The Social ◽  
Reference Collection ◽  
Grape Varieties ◽  
First Time

AbstractA crucial aspect of viticulture is finally unveiled as the historical dynamics of its agrobiodiversity are described in the Champagne region for the first time. Outline analyses were carried out to compare the morphology of archaeological grape seeds from Troyes and Reims (first c. AD to fifteenth c. AD) with that of a reference collection of modern seeds, including wild vines and traditional grape varieties, believed to be ancient and characteristic of the French vine heritage. This allows us to document the chronological dynamics of the use of the wild Vitis type and of the diversity of the varieties used, based on morphological disparity. After showing the existence of morphological types corresponding to geographical groups, we highlight a geochronological dynamic. Our results show that the wild type is used throughout the series, up to the Middle Ages. In addition, domestic forms, morphologically related to southern varietal groups, are very early involved in the Champagne grape agrodiversity. The groups corresponding to the typical grape varieties of today do not appear until the second millennium. These previously unsuspected dynamics are discussed in light of the social, societal and climatic changes documented for the period.

scholarly journals A Novel and Efficient High-Yield Method for Preparing Bacterial Ghosts

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 420
Author(s):  
Yi Ma ◽  
Liu Cui ◽  
Meng Wang ◽  
Qiuli Sun ◽  
Kaisheng Liu ◽  
...  
Keyword(s):  
Large Scale ◽  
Expression System ◽  
High Yield ◽  
Wild Type ◽  
High Quality ◽  
Efficient Protection ◽  
Bacterial Ghosts ◽  
Cell Envelopes ◽  
Extracellular Structures ◽  
First Time

Bacterial ghosts (BGs) are empty cell envelopes possessing native extracellular structures without a cytoplasm and genetic materials. BGs are proposed to have significant prospects in biomedical research as vaccines or delivery carriers. The applications of BGs are often limited by inefficient bacterial lysis and a low yield. To solve these problems, we compared the lysis efficiency of the wild-type protein E (EW) from phage ΦX174 and the screened mutant protein E (EM) in the Escherichia coli BL21(DE3) strain. The results show that the lysis efficiency mediated by protein EM was improved. The implementation of the pLysS plasmid allowed nearly 100% lysis efficiency, with a high initial cell density as high as OD600 = 2.0, which was higher compared to the commonly used BG preparation method. The results of Western blot analysis and immunofluorescence indicate that the expression level of protein EM was significantly higher than that of the non-pLysS plasmid. High-quality BGs were observed by SEM and TEM. To verify the applicability of this method in other bacteria, the T7 RNA polymerase expression system was successfully constructed in Salmonella enterica (S. Enterica, SE). A pET vector containing EM and pLysS were introduced to obtain high-quality SE ghosts which could provide efficient protection for humans and animals. This paper describes a novel and commonly used method to produce high-quality BGs on a large scale for the first time.

scholarly journals Characterization of a Novel Fructosyltransferase from Lactobacillus reuteri That Synthesizes High-Molecular-Weight Inulin and Inulin Oligosaccharides

2002 ◽  
Vol 68 (9) ◽  
pp. 4390-4398 ◽  
Author(s):  
S. A. F. T. van Hijum ◽  
G. H. van Geel-Schutten ◽  
H. Rahaoui ◽  
M. J. E. C. van der Maarel ◽  
L. Dijkhuizen
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Lactobacillus Reuteri ◽  
Bacterial Strains ◽  
Potential Health ◽  
Isolation And Characterization ◽  
A Cell ◽  
Encoding Gene ◽  
First Time

ABSTRACT Fructosyltransferase (FTF) enzymes produce fructose polymers (fructans) from sucrose. Here, we report the isolation and characterization of an FTF-encoding gene from Lactobacillus reuteri strain 121. A C-terminally truncated version of the ftf gene was successfully expressed in Escherichia coli. When incubated with sucrose, the purified recombinant FTF enzyme produced large amounts of fructo-oligosaccharides (FOS) with β-(2→1)-linked fructosyl units, plus a high-molecular-weight fructan polymer (>107) with β-(2→1) linkages (an inulin). FOS, but not inulin, was found in supernatants of L. reuteri strain 121 cultures grown on medium containing sucrose. Bacterial inulin production has been reported for only Streptococcus mutans strains. FOS production has been reported for a few bacterial strains. This paper reports the first-time isolation and molecular characterization of (i) a Lactobacillus ftf gene, (ii) an inulosucrase associated with a generally regarded as safe bacterium, (iii) an FTF enzyme synthesizing both a high molecular weight inulin and FOS, and (iv) an FTF protein containing a cell wall-anchoring LPXTG motif. The biological relevance and potential health benefits of an inulosucrase associated with an L. reuteri strain remain to be established.

Enzyme activity enhancement of chondroitinase ABC I from Proteus vulgaris by site-directed mutagenesis

RSC Advances ◽  
2015 ◽  
Vol 5 (93) ◽  
pp. 76040-76047 ◽  
Author(s):  
Zhenya Chen ◽  
Ye Li ◽  
Yue Feng ◽  
Liang Chen ◽  
Qipeng Yuan
Keyword(s):  
Active Site ◽  
Simulation Analysis ◽  
Docking Simulation ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Wild Type ◽  
Proteus Vulgaris ◽  
Molecular Docking Simulation ◽  
Activity Enhancement ◽  
First Time

Arg660 was found as a new active site and Asn795Ala and Trp818Ala mutants showed higher activities than the wild type based on molecular docking simulation analysis for the first time.

Abstract P283: Parkin Mediates Mitophagy in Cardioprotection

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Allen M Andres ◽  
Chengqun Huang ◽  
Eric P Ratliff ◽  
Genaro Hernandez ◽  
Pamela Lee ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Wild Type ◽  
Simulated Ischemia ◽  
Selective Targeting ◽  
Cardioprotective Effects ◽  
Mitochondrial Turnover ◽  
First Time

Autophagy-dependent mitochondrial turnover in response to cellular stress is necessary for maintaining cellular homeostasis. However, the mechanisms that govern the selective targeting of damaged mitochondria are poorly understood. Parkin, an E3 ubiquitin ligase, has been shown to be essential for the selective clearance of damaged mitochondria. Parkin is expressed in the heart, yet its function has not been investigated in the context of cardioprotection. We previously reported that autophagy is required for cardioprotection by ischemic preconditioning (IPC). In the present study, we used simulated ischemia in vitro and IPC in hearts (in vivo and ex vivo) to investigate the role of Parkin in mediating cardioprotection. In HL-1 cells, simulated ischemia induced Parkin translocation to mitochondria and mitochondrial elimination. Mitochondrial loss was blunted in Atg5-deficient cells, revealing the requirement for autophagy in mitochondrial elimination. Consistent with previous reports implicating p62/SQSTM1 in mitophagy, we found that downregulation of p62 attenuated mitophagy and exacerbated cell death in HL-1 cardiomyocytes subjected to simulated ischemia. While wild type mice showed p62 translocation to mitochondria after IPC, Parkin knockout mice exhibited attenuated translocation of p62 to mitochondria. Importantly, ablation of Parkin in mice abolished the cardioprotective effects of IPC. These results reveal for the first time the crucial role of Parkin and mitophagy in cardioprotection.

Efficacy of Cavern Isolates for Biodegradation of Synthetic Plastic

2021 ◽  
Vol 18 ◽  
Author(s):  
Jamila Tabassum ◽  
Muhammad Luqman ◽  
Fariha Hasan ◽  
Fariha Arooj ◽  
Saif Ur Rehman Kashif ◽  
...  
Keyword(s):  
Environmental Concern ◽  
Mechanical Damage ◽  
Bacterial Consortium ◽  
Alcaligenes Faecalis ◽  
Bacterial Strains ◽  
Ldpe Film ◽  
Intermediate Metabolites ◽  
Bacillus Sonorensis ◽  
Physical Changes ◽  
First Time

: Synthetic plastic waste management is a tenacious environmental concern at the global level. Although all types of synthetic plastics are a nuisance to the environment, however, versatility and one time use have made polyethylene (PE) a foremost environmental issue. The current study has investigated cavern bacterial strains isolated from PE samples from San Giovanni cave, Sardinia, Italy for their efficacy to biodegrade low-density polyethylene (LDPE) film. It was an initial effort to use cavern bacteria in plastic biodegradation studies. Chemical and physical changes in the composition of LDPE were studied by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) after incubation with the bacterial consortium for two months. Collected cavern PE plastic samples were also studied for biodegradation after incubation in nutrient broth for two months. FTIR revealed obvious signs of degradation with the appearance of two new peaks of functional groups, nitriles (C≡N) and amines (N-H) in LDPE film, which are intermediate metabolites of β- oxidation pathway. An increase in various existing peaks of several intermediate metabolites including aldehydes, ketones, alcohols, and carboxylic acids, were also observed in experimental LDPE compared to control. Peaks of alkanes decreased significantly owing to cavern bacterial activity. SEM revealed biofilm formation on experimental LDPE surface with substantial mechanical damage. Similar signs of degradation were observed in the cavern PE samples. Four bacterial strains in the current consortium, including Bacillus sonorensis, Bacillus subtilis, Aneurinibacillus spp., and Alcaligenes faecalis are first time reported to be linked with biodegradation of plastics. The cavern bacteria under study have the potential to biodegrade LDPE.

Diversity of nodular bacteria ofScorpiurus muricatusin western Algeria and their impact on plant growth

2017 ◽  
Vol 63 (5) ◽  
pp. 450-463 ◽  
Author(s):  
Zoulikha Bouchiba ◽  
Zineb Faiza Boukhatem ◽  
Zohra Ighilhariz ◽  
Nouria Derkaoui ◽  
Benaissa Kerdouh ◽  
...  
Keyword(s):  
Plant Growth ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Pcr Amplification ◽  
Nucleotide Sequencing ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Single Strain ◽  
Western Algeria ◽  
First Time

A total of 51 bacterial strains were isolated from root nodules of Scorpiurus muricatus sampled from 6 regions of western Algeria. Strain diversity was assessed by rep-PCR amplification fingerprinting, which grouped the isolates into 28 different clusters. Partial nucleotide sequencing of the 16S rRNA gene and BLAST analysis revealed that root nodules of S. muricatus were colonized by different species close to Rhizobium vignae, Rhizobium radiobacter, Rhizobium leguminosarum, Phyllobacterium ifriqiyense, Phyllobacterium endophyticum, Starkeya sp., and Pseudomonas sp. However, none of these strains was able to form nodules on its host plant; even nodC was present in a single strain (SMT8a). The inoculation test showed a great improvement in the growth of inoculated plants compared with noninoculated control plants. A significant amount of indole acetic acid was produced by some strains, but only 2 strains could solubilize phosphate. In this report we described for the first time the diversity of bacteria isolated from root nodules of S. muricatus growing in different regions in western Algeria and demonstrated their potential use in promoting plant growth.

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