Potrošnja ugljika i proizvodnja metabolita tijekom rasta plijesni Geotrichum candidum i Penicillium camemberti u podlozi s glukozom i aminokiselinama

Amino acids had previously been characterized based on their ability to be assimilated as carbon sources by Penicillium camemberti and Geotrichum candidum. For each microorganism, three groups of amino acids have been characterized, leading to four different metabolic behaviours. To describe those recorded during P. camemberti growth on an amino acid and glucose, an unstructured model had previously been developed, based on the sequential consumption of both carbon substrates; glucose first, followed after its exhaustion by the selected amino acid. Only the part of the amino acid assimilated as a carbon source for cellular biosynthesis was considered in the model, which had to be deduced from the total amino acid consumption. To avoid the use of such an indirect parameter, ammonium was considered in this work, which was produced after amino acid deamination and corresponded to the release of the excess nitrogen, since amino acids contain excess nitrogen in relation to their carbon content in fungi. The model, therefore, involved substrate carbon consumption, ammonium production, as well as biomass yield on the carbon substrate, YX/S, and biomass yield on the produced ammonium, YX/P. The model proved to describe satisfactorily the various metabolic behaviours recorded during P. camemberti and G. candidum growth on an amino acid and glucose.U ispitivanju su upotrijebljene aminokiseline prethodno okarakterizirane kao izvor ugljika za rast plijesni Geotrichum candidum i Penicillium camemberti. Za svaki su mikroorganizam karakterizirane tri skupine aminokiselina, čija se asimilacija odvija kroz jedan od četiriju različitih metaboličkih puteva. Prethodno je razvijen nestrukturirani model rasta P. camemberti u podlozi s aminokiselinom i glukozom, temeljen na potrošnji ugljika iz glukoze, pa nakon iscrpljivanja glukoze iz odabrane aminokiseline. U izračunu je modela uzet samo dio aminokiseline, asimiliran kao izvor ugljika pri biosintezi stanica plijesni, dobiven oduzimanjem dijela aminokiseline asimiliranog kao izvor dušika od ukupne potrošnje aminokiselina. Kako bi se izbjegla upotreba ovakva indirektnog parametra rasta, u model je uključena količina amonijaka dobivenog deaminacijom aminokiselina, koja odgovara količini oslobođenog dušika. Tako je naposljetku model obuhvaćao potrošnju ugljika, proizvodnju amonijaka, prinos biomase YX/S izračunat prema potrošnji ugljika i prinos biomase YX/P dobiven na osnovi količine proizvedenog amonijaka. Takav model uspješno opisuje različite metaboličke puteve asimilacije aminokiselina tijekom rasta P. camemberti i G. candidum u podlozi s aminokiselinom i glukozom

Études physiologiques et cinétiques de "geotrichum candidum" et "Penicillium camembertii" cultivés en bioréacteur sur milieux synthétiques

Des cultures des deux microflores d'affinage G. candidum et P. camembertii ont été menées en bioréacteur. Ce travail a montré que, contrairement à P. camembertii, en présence de substrats aisément assimilables en tant que sources de carbone, par exemple des peptones ou du glutamate, le lactate n'est pas consommé par G. candidum durant sa croissance. La culture mixte sur jus de camembert a mis en évidence des effets de synergie entre les deux microorganismes; les activités enzymatiques de G. candidum ont facilité l'assimilation de peptides et d'acides aminés comme sources de carbone par P. camembertii. Il y a de plus compétition entre les deux espèces pour les peptides et acides aminés les plus aisément métabolisables, qui sont ainsi utilisés comme sources d'énergie, en plus d'être sources de carbone et d'azote; les autres sources de carbone disponibles n'ont été utilisées que pour le maintien cellulaire. Cette compétition a été confirmée sur milieux synthétiques simples.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

The Substrate Carbon Consumption and Metabolite Production to Describe the Growth of Geotrichum candidum and Penicillium camemberti on Glucose and Amino Acids

Amino acids had previously been characterized based on their ability to be assimilated as carbon sources by Penicillium camemberti and Geotrichum candidum. For each microorganism, three groups of amino acids have been characterized, leading to four different metabolic behaviours. To describe those recorded during P. camemberti growth on an amino acid and glucose, an unstructured model had previously been developed, based on the sequential consumption of both carbon substrates; glucose first, followed after its exhaustion by the selected amino acid. Only the part of the amino acid assimilated as a carbon source for cellular biosynthesis was considered in the model, which had to be deduced from the total amino acid consumption. To avoid the use of such an indirect parameter, ammonium was considered in this work, which was produced after amino acid deamination and corresponded to the release of the excess nitrogen, since amino acids contain excess nitrogen in relation to their carbon content in fungi. The model, therefore, involved substrate carbon consumption, ammonium production, as well as biomass yield on the carbon substrate, YX/S, and biomass yield on the produced ammonium, YX/P. The model proved to describe satisfactorily the various metabolic behaviours recorded during P. camemberti and G. candidum growth on an amino acid and glucose

Energy Balance Of Third Generation Bioethanol

Global greenhouse gas emissions are constantly increasing, despite the partial replacement of fossil fuels by renewable energies. The transport sector is responsible for almost 24% of direct CO2 emissions from the combustion of fossil fuels, generating greenhouse gas emissions, highlighting the need for a greater focus of international policies to encourage the production and the use of biofuels. Bioethanol is the most consumed biofuel in the world; it is produced by fermentation from materials rich in sugar (glucose, starch, cellulose). However, the controversy around the use of first and second generation have forced the transition to the third generation based on marine and freshwater algae; the latter have the advantage of being abundant, even invasive, easy to cultivate with good energy potential. This study proposes a life cycle analysis (LCA) of bioethanol production from the macro algae Ulva Lactuca, it was carried out after the introduction of several data into the SimPro8.1 software (e.g. quantity of water, consumed electricity, used chemicals) using the Impact 2002+ methodology. The results show a positive energy balance reflecting high-energy efficiency since the system produces about 1.44 times the energy consumed

Enhancement of indigenous microalgae culture using cheese whey as growth media for bioenergy and coproducts production

This study investigates the use of cheese whey to enhance the microalgae cultivation for bioenergy and coproducts in the framework of circular economy and pollution attenuation. A local isolated indigenous Chlorella vulgaris strain using a growth medium containing BG11 and cheese whey (BG11/CW) was used. Algae density, dry weight, organic carbon consumption, biochemical composition, fatty acid profile, Total pigments were investigated. The best growth is obtained in the BG11/CW culture media, with a dry biomass and cell density of 2.5 g/L, 6.5×107 Cells/ml, respectively. This represents 5 times the dry biomass obtained in the BG11medium (0.45 g/L, 1.68×107 cells/ml). Indigenous Chlorella vulgaris growth is favored by glycose availability after lactose degradation with a consumption of 62% on the 7th day. Pigments content was improved with an average value of 34.5 mg/gDW and 9 mg/mgDW for total chlorophylls and carotenoids, respectively. Chlorella vulgaris cultivation on BG11/CW has showed a high protein content with a value of 46%. Indigenous Chlorella vulgaris was able to accumulate a suitable lipid content that could reach 23%, which are rich in C16:00, C18:00, C18:1. This strain is a potential candidate for a sustainable bioenergy and coproducts that could contribute efficiently to promote the circular economy

CELLULOSIC BIOETHANOL PRODUCTION FROM ULVA LACTUCA MACROALGAE

International audienceNowadays, the use of biofuels has become an unavoidable solution to the depletion of fossil fuels and global warming. The controversy over the use of food crops for the production of the first-generation biofuels and deforestation caused by the second-generation ones has forced the transition to the third generation of biofuels, which avoids the use of arable land and edible products, and does not threaten biodiversity. This generation is based on the marine and freshwater biomass, which has the advantages of being abundant or even invasive, easy to cultivate and having a good energetic potential. Bioethanol production from Ulva lactuca, a local marine macroalgae collected from the west coast of Algiers, was examined in this study. Ulva lactuca showed a good energetic potential due to its carbohydrate-rich content: 9.57% of cellulose, 6.9% of hemicellulose and low lignin content of 5.11%. Ethanol was produced following the separate hydrolysis and fermentation process (SHF), preceded by a thermal acid pretreatment at 120 degrees C during 15 min. Enzymatic hydrolysis was performed using a commercial cellulase (Celluclast 1.5 L), which saccharified the cellulose contained in the green seaweed, releasing about 85.01% of the total glucose, corresponding to 7.21 g/L after 96 h of enzymatic hydrolysis at pH 5 and 45 degrees C. About 3.52 g/L of ethanol was produced after 48 h of fermentation using Saccharomyces cerevisiae at 30 degrees C and pH 5, leading to a high ethanol yield of 0.41 g of ethanol/g of glucose

ISOLATION AND IDENTIFICATION OF YEAST STRAINS FROM SUGARCANE MOLASSES, DATES AND FIGS FOR ETHANOL PRODUCTION UNDER CONDITIONS SIMULATING ALGAL HYDROLYSATE

International audienceYeast strains were isolated from sugar cane molasses (S1), dates (S2) and figs (S3) and the ethanol production was evaluated in batch condition. A comparison was made with the yeast Saccharomyces cerevisiae. The strains showed tolerant characteristics to stressful conditions like salinity and ethanol. The isolated strains produced ethanol; at 20 h of fermentation ethanol yields were 0.38-0.39 g.g-1 , and the productivities were almost 0.58 g.L-1. S. cerevisiae and S1 tolerated up to 14% (v/v) of ethanol; while interestingly the isolates S2 and S3 were highly tolerant, up to 20% (v/v) ethanol. Thus, S2 and S3 could serve as potential strains for ethanol fermentation, with 0.27 and 0.29 g.g-1 yield of ethanol in the presence of 1.37 mol.L-1 NaCl. These values were higher than the value obtained using the yeast of reference and S1 (0.16 g.g-1). Co-cultures of S2 and S3 enhanced the ethanol production, increasing the yield of ethanol by 12.5% compared with the single culture. The strains were identified as species S.cerevisiae, and S2 and S3 were very similar. For an application in the valorization of biomass such as green macro-algae, some assays were done on a synthetic model medium of hydrolysate of macro-algae and the strains S2 and S3 demonstrated excellent fermentative performances

Experimental study and kinetic modelling of bioethanol production from industrial potato waste

International audienceThe potato wastes constitute a major environmental concern due to their significant production in the potato processing industry. Due to their high organic content, this waste can constitute a very interesting Algerian resource for biofuel production. The objective of this study is the energy recovery of an industrial agro-food waste to produce bioethanol. This waste is a solid residue of chips manufacturing and mainly consists of potato starch. The conversion of this biomass was achieved using a chemical pretreatment with hydrochloric acid. The acid hydrolysis of potato starch with a ratio of material to acid solution of 1:2 (w/v) was enough to liberate a high amount of fermentable reducing sugar (159.3 g/l) contained in the potato waste. The hydrolysate obtained at the end was fermented using Saccharomyces cerevisiae yeast under the following conditions (pH 5, 30 degrees C, 100 rpm). The maximum yield of bioethanol (54.12 g/l) was achieved after 116 h. Thus, operating conditions used for the sugar fermentation were favorable and did not exhibit any sort of process inhibition. The Gompertz model was applied to experimental data, and kinetic fermentation parameters such as maximum ethanol concentration (P-m = 49.81 g/l), production rate (r(pm) = 0.87 g/(l h)), and lag phase (t(L) = 5.29 h) were accurately estimated. Those parameters can be used to investigate the economical feasibility for such industry. The results demonstrate that potato starch (by-product of the potato industry) has a great potential for bioethanol production

Direct structural identification of polysaccharides from red algae by FTIR microspectrometry I: Localization of agar inGracilaria verrucosa sections

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Indigenous microalgae strains characterization for a sustainable biodiesel production

International audienceMicroalgae have been widely recognized as a promising feedstock for sustainable biofuels production to tackle global warming and pollution issues related to fossil fuels uses. This study identified and analyzed indigenous microalgae strains for biodiesel production, specifically Chlorella vulgaris and Coelastrella thermophila var. globulina, from two distinct locations in Algeria. Molecular identification confirmed their identity, and the microalgae exhibited notable growth characteristics. Local Chlorella vulgaris and Coelastrella thermophila var. globulina showed a good growth and high biomass yield, compared to Chlorella vulgaris CCAP211/11B reaching a weight of 1.48 g/L, 1.95g/L and 2.10 g/L, respectively. Lipids content of local Chlorella vulgaris, Coelastrella thermophila var. globulina, and Chlorella vulgaris CCAP211/11B, were found to be 31.39 ± 3.3%, 17 ± 2.26%, and 19 ± 0.64%, respectively. Chlorella vulgaris stood out as a candidate for biodiesel production due to its equilibrium between SFA and PUFA (43.24% and 45.27%). FAs are predominated by SFA and MUFA for Coelastrella thermophila var. globulina with value of 81.49% (SFA+MUFA). Predicted biodiesel qualities are complying with ASTM6751 and EN14214 standards. Studied microalgae have therefore a promising potential for biodiesel production. However, optimising cultivation conditions is necessary to enhance biomass and lipids yield at large scale. This article is protected by copyright. All rights reserved