Liquid membrane extraction of bio-active amphiphilic substances: Recovery of surfactin

The interest of application of liquid membrane (pertraction) processes for recovery of biosurfactants from aqueous media was demonstrated. Transport of pure surfactin in three-liquid-phase system was studied. Surfactin was successfully extracted from slightly acid media (pH 5.65–6.05) applying batch pertraction in a rotating discs contactor and using n-heptane as liquid membrane. The process efficiencywas found to be strongly affected by the feed solution acidity (83% at pHF 6.05 and 97% at pHF 5.65 after 4 h pertraction). An atypical pH effect was observed when the behaviour of surfactin extraction from aqueous media by non-polar solvents (n-heptane and n-octane)was studied. The obtained high extraction degrees fromboth acid and basic media and the clearly reduced degree of extraction from neutral media could be attributed to the different conformations of surfactin in these media

Liquid membrane extraction lipopeptides

Liquid membrane extraction lipopeptide

Lipopeptide overproduction by cell immobilization on iron-enriched light polymer particles

The study concerns surfactin and/or fengycin batch production by immobilized cells of Bacillus subtilis ATCC 21332. Light carriers designed for a three phase inverse fluidized bed biofilm reactor (TPFIBR) were used. With respect to the biofilm reactor development, a new support based on iron grafting onto polypropylene foams has been proposed. A suspension solid-state grafting process was applied to graft ferric acetylacetonate onto polypropylene (PP) foams with a density of 0.3–0.7 g/cm3. The iron contents grafted onto PP increased with the reaction time and then it tended to level off. The iron contents at 7.5 and 10 h are 0.74 and 0.75 wt%, respectively. It was specified that the equilibrium was reached at 7.5 h. Influence of particles on lipopeptide production was analyzed in two kinds of experiments: preliminary colonization step of particles, followed by production step in modified culture medium (named in this work colonization step) or direct addition of pellets in culturemedium (named production step). All PP+ iron pellets promoted biomass enhancement. The production yield was modified for all types of PP supports, containing respectively 0, 0.35 and 0.75% of iron. The immobilized cultures produced 2.09–4.3 times more biosurfactants than planktonic cells. In production experiments addition of carriers seemed tomodify the ratio between surfactin and fengycin with an enhancement of the fengycin production. The highest concentration of fengycin was obtained with addition of pellets containing 0.35% of iron

Integrated process for production of surfactin Part 1: Adsorption rate of pure surfactin onto activated carbon

The work reported in this paper is aimed at studying the adsorption of surfactin from aqueous solution onto activated carbon. Among the factors,agitation rate, activated carbon particle-size, pH, temperature, initial adsorbate concentration, adsorbent amount and ionic strength of the solution were studied. Both adsorption equilibrium and kinetics showed that activated carbon acted as a suitable adsorbent for surfactin recovery. Two mechanisms represented by different kinetic models were examined, namely, the intraparticle diffusion one and the one involving chemisorption accompanied by surface coverage (conforming to the Elovich concept)

Integrated process for production of surfactin Part 2. Equilibrium and kinetic study of surfactin adsorption onto activated carbon

Previous work has presented kinetics of pure surfactin adsorption onto activated carbon. Being an efficient biosurfactant, the lipopeptide surfactin has been produced in a bioprocess supported by the strain Bacillus subtilis ATCC 21332. This work is aimed at studying surfactin recovery directly from the culture medium. A thermodynamic study is carried out. Referring to adsorption capacity, the thermodynamic study confirmed that the adsorption of pure surfactin is an exothermic process. The capacity of surfactin adsorption from culture media shows that the activated carbon could be used as efficient adsorbent for surfactin recovery in an integrated process. The study shows the importance of the temperature for process control. Aimed at fixed bed column design, surfactin adsorption modelling on a single microporous pellet is demonstrated

Use of settlement patterns and geochemical tagging to test population connectivity of eastern oysters Crassostrea virginica

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gancel, H. N., Carmichael, R. H., Du, J., & Park, K. Use of settlement patterns and geochemical tagging to test population connectivity of eastern oysters Crassostrea virginica. Marine Ecology Progress Series, 673, (2021): 85–105, https://doi.org/10.3354/meps13796.Freshwater-dominated estuaries experience large fluctuations in their physical and chemical environments which may influence larval dispersal, settlement, and connectivity of populations with pelagic larval stages. We used settlement patterns and natural tagging along with numerical hydrodynamic model results to assess settlement and connectivity among oysters across the freshwater-dominated Mobile Bay-eastern Mississippi Sound (MB-EMS) system. Specifically, we (1) tested how freshwater inputs and associated environmental attributes influenced settlement patterns during high and low discharge conditions in 2014 and 2016, respectively, and (2) analyzed trace element (TE) ratios incorporated into multiple shell types (larval and settled shell of spat and adult shells) to determine if shells collected in situ incorporate temporally stable site-specific signatures. We also assessed if TE ratios compared between adult (TE natal signature proxy) and larval shells could infer connectivity. Larval settlement was 4× higher during low discharge than during high discharge when oyster larvae only settled in higher salinity regions (EMS). Spat and adult shells incorporated site-specific TE ratios that varied from weeks to months. Connectivity results (May-June 2016 only) suggest that EMS is an important larval source to EMS and lower MB. While we were able to infer probable connectivity patterns using adult and larval shells, more study is needed to assess the utility of adult shells as proxies for natal-location TE signatures. Results provide a baseline for measuring future larval connectivity and adult distribution changes in the MB-EMS system. Biological and geochemical data demonstrate the potential to identify environmental attributes that spatiotemporally mediate settlement and connectivity in dynamic systems.This work was funded by the Mississippi−Alabama Sea Grant Consortium (project number #R/ SFA-03) and the Food and Drug Administration and MESC/ Dauphin Island Sea Lab Collaboration (award numbers: 5U19FD005923-04 and 5U19FD004277-04)

Migration of polyphenols from natural and microagglomerated cork stoppers to hydroalcoholic solutions and their sensory impact

During bottling aging, the wine comes into contact with the cork stopper due to the horizontal position of the bottle. The release of compounds, such as cork phenolic compounds, thus take place between the cork and the wine, depending on the type of cork stopper and the surface treatments applied. Many publications describe the extraction of these phenolic compounds in wine or hydroalcoholic solutions from natural corks, but few address microagglomerated corks, which are increasingly used by winemakers to seal their bottles. The aim of this study was therefore to compare the polyphenols, mainly hydrolysable tannins, transferred from natural and microagglomerated corks treated with supercritical CO2 into hydroalcoholic solutions. For this purpose, polyphenols released in macerates of natural and microagglomerated cork stoppers were identified and quantified by HPLC-DAD-ESI-QQQ. Suberic acid was also quantified. In this study, despite the high intra-“natural cork stopper” variability, significant differences were found between both types of stoppers for all polyphenols, the agglomerated corks releasing significantly less polyphenols; i.e., 25 times less. In contrast, suberic acid was extracted from both types of corks in similar concentrations; therefore, its extractability was not impacted by the type of stopper. A sensory profile was also carried out on the macerates. Macerates of natural cork stoppers were perceived with notes of “cardboard, dust, plank, wood” and “cork taint” significantly higher than supercritical CO2 treated microagglomerated cork stopper macerates. Moreover, the natural cork macerate with the highest content in polyphenol was perceived as being more bitter than that of microagglomerated cork stoppers

Wine acidification methods: a review

Global warming is directly linked to a lower concentration in organic acids in grape berries, leading to higher pHs in wine. Because of this lack of acidity, many important factors are impacted, as wine acidity and pH play a crucial role in various equilibriums. Indeed, the lower acidity and the higher pH modify the parameters of wine, such as free and molecular sulfur dioxide availability, colour and sensory aspects. Therefore, it is an ongoing challenge for winemakers to deal with wine acidification and thus preserve wine physico-chemical properties and prevent early spoilage due to microbiological instability induced by high pH. Different acidification methods are allowed by the OIV, chemical acidification being one the most common, followed by physical acidification and microbiological acidification. This review examines these three methods of acidification. The first part details chemical acidification and gives a complete description of various organic acids used in winemaking, and their different properties and regulations; the second part focuses on physical acidification, such as cation exchange resins and electrodialysis; and the last part briefly reviews the novelty of microbiological acidification in wine