Knockout of pgdS and ggt genes improves γ‐PGA yield in B. subtilis

Scoffone, Viola Camilla; Dondi, Daniele; Biino, Ginevra; Borghese, Giovanni; Pasini, Dario; Galizzi, Alessandro; Calvio, Cinzia

doi:10.1002/bit.24846

Cited by 74 publications

(66 citation statements)

References 39 publications

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“…However, their industrial utilization is limited due to lower c-PGA productivity compared with those of L-glutamate-dependent producers. This has led to the development of genetically engineering non-glutamatedependent producers such as B. amyloliquefaciens NK-1 (Feng et al, 2014) as well as laboratory strains such as B. subtilis MA41 (Ashiuchi et al, 2006), E. coli (Cao et al, 2013) and B. subtilis 168 (Scoffone et al, 2013) for high c-PGA productivity.…”

Section: Production Of C-pga By Microbial Fermentationmentioning

confidence: 99%

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Poly-γ-glutamic acid: production, properties and applications

et al. 2015

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Section: Production Of C-pga By Microbial Fermentationmentioning

confidence: 99%

“…c-PGA production was recently evaluated by Scoffone et al (2013). This was done by knocking out pgdS and ggt (genes for two important c-PGA-degrading enzymes) in the laboratory strain B. subtilis 168.…”

Section: B Subtilismentioning

confidence: 99%

Poly-γ-glutamic acid: production, properties and applications

et al. 2015

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“…In many cases, the preparation of γ-PGA from Bacillus sp. is carried out only by ethanol precipitation (Berekaa et al, 2009;Kongklom et al, 2012;Scoffone et al, 2013;Zhao et al, 2013). Therefore, it was performed in the same way here.…”

Section: Enantiomeric Composition Of γ-Pgamentioning

confidence: 99%

Flocculation of Real Sewage Sludge Using Poly-γ-glutamic Acid Produced by Bacillus sp. Isolated from Soil

Liu

Yamashita

Tachibana

et al. 2017

J. Chem. Eng. Japan / JCEJ

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To promote the use of sewage sludge on farmland, a occulant compatible with agricultural application is required. In general, an inorganic occulant such as aluminium sulfate is used at large sewage disposal plants. However, there is concern that aluminium accumulates when it is returned to farmland, and therefore a biodegradable rather than an inorganic occulant is required. To obtain biodegradable occulants produced by microorganisms, the latter were isolated from soils and sewage sludges, and the occulation activity of the culture broths was evaluated. Here, real sewage sludge was used for the evaluation because practical use was regarded as an important consideration. As a result, two strains, V13 and RK14, were selected and identi ed as Bacillus megaterium and Bacillus licheniformis, respectively. It was also found that occulation was caused by poly-γ-glutamic acid (γ-PGA). γ-PGA from RK14 cells had considerably higher molecular weight than commercial γ-PGA, and the enantiomeric composition di ered from that of γ-PGA from other B. licheniformis. To obtain mutants with high γ-PGA productivity, RK14 cells were treated with ethyl methanesulfonate, and a mutant (RK14-46) was selected. The culture medium suitable for γ-PGA production by RK14-46 cells was totally di erent from that by RK-14 cells. The γ-PGA production reached 21.1 g/L when RK14-46 cells were cultured in the optimum semisynthetic medium at 30°C for 2 d. Furthermore, the combination of γ-PGA obtained from RK14-46 cells and chitosan, a cationic occulant, was very e ective for occulation of real sewage sludge.

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“…A second biofilm matrix protein, BslA, is a self-assembling hydrophobin on the surface of B. subtilis NCIB 3610 biofilms (49,50). In contrast to that of strain NCIB 3610, the biofilm matrix of the wild-type strain B. subtilis B-1 is described as being composed mainly of ␥-polyglutamate (␥-PGA) (51), a highly hydrophilic anionic polymer (52).…”

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confidence: 99%

Direct Comparison of Physical Properties of Bacillus subtilis NCIB 3610 and B-1 Biofilms

Kesel

Grumbein

Gümperlein

et al. 2016

Appl Environ Microbiol

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cMany bacteria form surface-attached communities known as biofilms. Due to the extreme resistance of these bacterial biofilms to antibiotics and mechanical stresses, biofilms are of growing interest not only in microbiology but also in medicine and industry. Previous studies have determined the extracellular polymeric substances present in the matrix of biofilms formed by Bacillus subtilis NCIB 3610. However, studies on the physical properties of biofilms formed by this strain are just emerging. In particular, quantitative data on the contributions of biofilm matrix biopolymers to these physical properties are lacking. Here, we quantitatively investigated three physical properties of B. subtilis NCIB 3610 biofilms: the surface roughness and stiffness and the bulk viscoelasticity of these biofilms. We show how specific biomolecules constituting the biofilm matrix formed by this strain contribute to those biofilm properties. In particular, we demonstrate that the surface roughness and surface elasticity of 1-day-old NCIB 3610 biofilms are strongly affected by the surface layer protein BslA. For a second strain, B. subtilis B-1, which forms biofilms containing mainly ␥-polyglutamate, we found significantly different physical biofilm properties that are also differently affected by the commonly used antibacterial agent ethanol. We show that B-1 biofilms are protected from ethanol-induced changes in the biofilm's stiffness and that this protective effect can be transferred to NCIB 3610 biofilms by the sole addition of ␥-polyglutamate to growing NCIB 3610 biofilms. Together, our results demonstrate the importance of specific biofilm matrix components for the distinct physical properties of B. subtilis biofilms. Bacteria embed themselves with secreted biopolymers (1-3), building a community that is referred to as a biofilm. Such biofilms can be formed by a variety of Gram-positive as well as Gram-negative bacteria (4). The composition of the biofilm matrix is dependent on the biofilm-forming bacterium and environmental conditions such as shear forces experienced, temperature, and nutrient availability (5); the matrix can consist of different extracellular polymeric substances (EPSs), such as polysaccharides, proteins, lipids, and nucleic acids (6). Biofilms can grow on various surfaces (7-9). While Bacillus subtilis biofilms are formed on solid nutrient surfaces or at liquid-air interfaces (10, 11), other bacteria can produce biofilms on surfaces under water-saturated conditions (in liquid) (12). Due to their high mechanical stability (13,14) and their resistance to antibiotic or chemical treatment (15-18), such biofilms present significant problems in both industry and health care (19)(20)(21)(22). Although the compositions of many biofilm matrices are known, the biomolecular reason for the outstanding resistance of bacterial biofilms is not well understood. Only a few studies have investigated the influence of specific matrix components on the mechanical properties of biofilms (23, 24). The majority of recent studies...

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Knockout of pgdS and ggt genes improves γ‐PGA yield in B. subtilis

Cited by 74 publications

References 39 publications

Poly-γ-glutamic acid: production, properties and applications

Poly-γ-glutamic acid: production, properties and applications

Flocculation of Real Sewage Sludge Using Poly-γ-glutamic Acid Produced by <i>Bacillus</i> sp. Isolated from Soil

Direct Comparison of Physical Properties of Bacillus subtilis NCIB 3610 and B-1 Biofilms

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