Purpose
Microbial fermentation on agro-industrial co-products is an interesting strategy for the bioproduction of metabolites of interest, as it lowers the costs of production and uses renewable and ...abundant carbon sources. Violacein is a purple pigment with interesting properties that is commonly produced by fermentation.
Chromobacterium vaccinii
, a wild-type, natural and non-toxic Proteobacteria (Pseudomonadota), has the ability to produce violacein. However, to select an optimal co-product as carbon source, it is necessary to understand its use of the different constituents of plant biomass.
Methods
Growth and violacein production of
C
.
vaccinii
were first studied on the main components of plant biomass. Then, they were assessed in presence of raw co-products at various concentrations. Tryptophan, a precursor of violacein biosynthesis, was added in order to evaluate the impact on violacein production yields.
Results
C
.
vaccinii
was able to grow on gluten (wheat protein), as well as on low concentrations of glucose. Selecting protein-rich substrates such as soybean and rapeseed cakes led to improved growth and violacein bioproduction. Addition of tryptophan led to net increases in violacein, but had low impacts on the bacterial growth.
Conclusion
Understanding microbial growth mechanisms during bioproduction of molecules of interest is key in order to select the best adapted agro-industrial co-products used as substrate. This study allowed to better characterize growth of
C
.
vaccinii
on various carbon sources and plant biomass, and showed that an optimal substrate with the addition of tryptophan could increase greatly the bioproduction yields of violacein by
C
.
vaccinii
.
Graphical abstract
•Proof of concept of growth on wheat bran for four microorganisms.•Selection of plant biomass-consuming microorganisms can be performed using carbohydrates and proteases specific ...databases.•Degradation of wheat bran can be followed with Fourier Transform Infra-Red spectroscopy coupled to enzyme activity analysis.•Carotenoids, flexirubin and canthaxanthin can be produced from a cheap and renewable carbon source.
Pigments are compounds with highly diverse structures and wide uses, which production is increasing worldwide. An eco-friendly method of bioproduction is to use the ability of some microorganisms to ferment on renewable carbon sources. Wheat bran (WB) is a cheap and abundant lignocellulosic co-product of low recalcitrance to biological conversion. Microbial candidates with theoretical ability to degrade WB were first preselected using specific databases. The microorganisms were Ashbya gossypii (producing riboflavin), Chitinophaga pinensis (producing flexirubin), Chromobacterium vaccinii (violacein) and Gordonia alkanivorans (carotenoids). Growth was shown for each on minimal salt medium supplemented with WB at 5 g.L−1. Activities of the main enzymes consuming WB were measured, showing leucine amino-peptidase (up to 8.45 IU. mL−1) and β-glucosidase activities (none to 6.44 IU. mL−1). This was coupled to a FTIR (Fourier Transform Infra-Red) study of the WB residues that showed main degradation of the WB protein fraction for C. pinensis, C. vaccinii and G. alkanivorans. Production of the pigments on WB was assessed for all the strains except Ashbya, with values of production reaching up to 1.47 mg.L−1. The polyphasic approach used in this study led to a proof of concept of pigment production from WB as a cheap carbon source.
Microalgae are regarded as promising organisms to develop innovative concepts based on their photosynthetic capacity that offers more sustainable production than heterotrophic hosts. However, to ...realize their potential as green cell factories, a major challenge is to make microalgae easier to engineer. A promising approach for rapid and predictable genetic manipulation is to use standardized synthetic biology tools and workflows. To this end we have developed a Modular Cloning toolkit for the green microalga Chlamydomonas reinhardtii. It is based on Golden Gate cloning with standard syntax, and comprises 119 openly distributed genetic parts, most of which have been functionally validated in several strains. It contains promoters, UTRs, terminators, tags, reporters, antibiotic resistance genes, and introns cloned in various positions to allow maximum modularity. The toolkit enables rapid building of engineered cells for both fundamental research and algal biotechnology. This work will make Chlamydomonas the next chassis for sustainable synthetic biology.
We tested the hypothesis that calling emergency medical services ("15", French equivalent of 911 or 999 calls) and response by a mobile intensive care unit staffed by emergency physicians (MICU) ...reduces the time to treatment to within the 3-hour time window required for administration of recombinant tissue plasminogen activator.
This study compared the time from symptom onset to admission (prehospital time), from admission to treatment (imaging and treatment delays, hospital time), and total time from symptom onset to treatment in an observational cohort of 53 consecutive patients, according to how they reached the hospital (Group 1: MICU and group 2: standard emergency ambulance dispatched by EMS center 2a or direct admission 2b).
The study included 52 patients (1 was excluded because hospitalized at the time of the stroke): 27 (51.9%) in group 1, 16 (30.8%) in group 2a, and 9 (17.3%) in group 2b. Calling "15" shortened total home-to-needle time by 24 minutes (p=0.034). The mean total time was not significantly shorter in group 1 (152 versus 162 min; p=0.27) but MICUs were used for patients farther away (mean distance 25 versus 11 km; p=0.02). The average prehospital time was thus higher in group 1 (86 versus 69 min; p=0.044), but was compensated by a reduction in the average hospital time (66 versus 93 min; p=0.0001), due mainly to shorter waits for imaging (22 versus 45 min; p=0.0001).
Calling the emergency services number reduces mean total time. MICUs were associated with a longer prehospital time, mainly due to greater distances, but they facilitated in-hospital management.
Nous avons testé l’hypothèse que l’appel du centre 15 et qu’une médicalisation préhospitalière permettrait de fluidifier la filière des infarctus cérébraux de moins de 3
heures, et de réduire les ...délais avant administration du rt-PA.
Nous avons comparé les délais préhospitaliers (délai d’admission) et hospitaliers (délai d’imagerie et de traitement) d’une cohorte observationnelle de 53 patients consécutifs traités, en fonction de leur mode d’admission (groupe 1 : sortie Smur et groupe 2 : acheminement sans médicalisation après 2a ou sans appel du 15 2b).
Vingt-sept patients (51,9 %) ont été admis après sortie Smur (groupe 1), 16 (30,8 %) régulés sans sortie Smur (groupe 2a), 9 (17,3 %) directement admis au SAU (groupe 2b) et 1 exclu de l’analyse car déjà hospitalisé lors de l’infarctus cérébral. L’appel du centre 15 a diminué les délais totaux de 24
min (p
=
0,034). Lors d’une sortie Smur, le délai total moyen n’était pas significativement réduit (152
versus 162
min ; p
=
0,27), mais pour une distance moyenne supérieure (25
versus 11
km ; p
=
0,02) le délai d’admission moyen était augmenté (86
versus 69
min ; p
=
0,044), compensé par une réduction du délai intrahospitalier moyen (66
versus 93
min ; p
=
0,0001) essentiellement au bénéfice du délai d’imagerie (22
versus 45
min ; p
=
0,0001).
Pour les infarctus cérébraux, l’appel du Samu a permis de réduire le délai total moyen avant administration du rt-PA. Le retentissement d’une sortie Smur est plus nuancé du fait d’une distance moyenne supérieure mais permet de mieux coordonner la prise en charge intrahospitalière.
We tested the hypothesis that calling emergency medical services (“15”, French equivalent of 911 or 999 calls) and response by a mobile intensive care unit staffed by emergency physicians (MICU) reduces the time to treatment to within the 3-hour time window required for administration of recombinant tissue plasminogen activator.
This study compared the time from symptom onset to admission (prehospital time), from admission to treatment (imaging and treatment delays, hospital time), and total time from symptom onset to treatment in an observational cohort of 53 consecutive patients, according to how they reached the hospital (Group 1: MICU and group 2: standard emergency ambulance dispatched by EMS center 2a or direct admission 2b).
The study included 52 patients (1 was excluded because hospitalized at the time of the stroke): 27 (51.9%) in group 1, 16 (30.8%) in group 2a, and 9 (17.3%) in group 2b. Calling “15” shortened total home-to-needle time by 24
minutes (p
=
0.034). The mean total time was not significantly shorter in group 1 (152
versus 162
min; p
=
0.27) but MICUs were used for patients farther away (mean distance 25
versus 11
km; p
=
0.02). The average prehospital time was thus higher in group 1 (86
versus 69
min; p
=
0.044), but was compensated by a reduction in the average hospital time (66
versus 93
min; p
=
0.0001), due mainly to shorter waits for imaging (22
versus 45
min; p
=
0.0001).
Calling the emergency services number reduces mean total time. MICUs were associated with a longer prehospital time, mainly due to greater distances, but they facilitated in-hospital management.
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