Biorefinery is the ideal model to help marine industries to apply green and blue economy principles towards a more sustainable, profitable, and conscious ocean economy.
Solvents that stabilize protein structures can improve and expand their biochemical applications, particularly with the growing interest in biocatalytic-based processes. Aiming to select novel solvents for protein stabilization, we explored the effect of alkylammonium nitrate protic ionic liquids (PILs)-water mixtures with increasing cation alkyl chain length on lysozyme conformational stability. Four PILs were studied, that is, ethylammonium nitrate (EAN), butylammonium nitrate (BAN), hexylammonium nitrate (HAN), and octylammonium nitrate (OAN). The surface tension, viscosity, and density of PIL-water mixtures at low to high concentrations were firstly determined, which showed that an increasing cation alkyl chain length caused a decrease in the surface tension and density as well as an increase in viscosity for all PIL solutions. Small-angle X-ray scattering (SAXS) was used to investigate the liquid nanostructure of the PIL solutions, as well as the overall size, conformational flexibility and changes to lysozyme structure. The concentrated PILs with longer alkyl chain lengths, i.e., over 10 mol% butyl-, 5 mol% hexyl- and 1 mol% octylammonium cations, possessed liquid nanostructures. This detrimentally interfered with solvent subtraction, and the more structured PIL solutions prevented quantitative SAXS analysis of lysozyme structure. The radius of gyration (Rg) of lysozyme in the less structured aqueous PIL solutions showed little change with up to 10 mol% of PIL. Kratky plots, SREFLEX models, and FTIR data showed that the protein conformation was maintained at a low PIL concentration of 1 mol% and lower when compared with the buffer solution. However, 50 mol% EAN and 5 mol% HAN significantly increased the Rg of lysozyme, indicating unfolding and aggregation of lysozyme. The hydrophobic interaction and liquid nanostructure resulting from the increased cation alkyl chain length in HAN likely becomes critical. The impact of HAN and OAN, particularly at high concentrations, on lysozyme structure was further revealed by FTIR. This work highlights the negative effect of a long alkyl chain length and high concentration of PILs on lysozyme structural stability.
Aqueous
biphasic systems (ABSs) based on sodium polyacrylate (NaPA),
ethylene oxide/propylene oxide (EO/PO) polymers, and (EO)
x
-(PO)
y
-(EO)
x
triblock copolymers were prepared and applied aiming
at continuous fructooligosaccharide (FOS) production and separation.
EO/PO hydrophilicity/hydrophobicity balance had a significant effect
on ABS formation. To develop an integrated process including the continuous
enzymatic (levansucrase) production of FOSs and their purification
while improving the production yield by further glucose separation,
the potential of these novel polymer-based ABSs as alternative platforms
was investigated. They were used for the partitioning of different
carbohydrates (FOS, sucrose, d-fructose, and d-glucose)
and levansucrase. Results revealed a highly polymer-dependent partition
of carbohydrates and a poorly dependent one of the enzymes. Changing
EO/PO and copolymers, FOS was purified with high yields (72.94–100.0%).
Using polypropylene glycol 400 + NaPA 8000-based ABS, the FOS was
precipitated in the interphase and separated from the other components.
Pluronic PE-6800 + NaPA 8000 was identified as the best ABS for FOS
continuous production and in situ purification, while minimizing levansucrase
inhibition by d-glucose. This system allowed selective partition
of FOSs and d-glucose toward the top phase and that of levansucrase
and its substrates toward the bottom one. COnductor-like Screening
MOdel for Real Solvent (COSMO-RS) suggested that ABS formation may
have been due to NaPA and polymer/copolymer competition to form hydrogen
bonds with water molecules. Moreover, the partition of FOSs and sugar
may have been the result of a subtle balance between hydrogen bonding
of sugar and polymer/copolymer and electrostatic misfit of solute
with NaPA. Finally, two integrated processes were proposed to be applied
with real FOS extracts obtained by chemical or enzymatic hydrolysis
of inulin or by transfructosylation of concentrated sucrose solutions
using bacterial levansucrases.
Aims: This study aims to demonstrate the potential of the lactic acid bacteria (LAB)Pediococcus pentosaceus LBM18 against the mycotoxin-producing Alternaria alternata TEF-1A and highlight its application as an effective grain silage inoculant to control mycotoxin contamination.
Methods and Results:The antifungal properties of Ped. pentosaceus lyophilized (PPL) were assessed by evaluating its effect on A. alternata TEF-1A grown in a corn silage-based medium, which included morphological changes by Scanning Electron Microscopy (SEM) observations, growth rate, conidia production assays, and inhibition of Tenuazonic acid (TeA) production by high-performance liquid chromatography (HPLC-MS/MS) analyses. Furthermore, TeA biosynthesis was monitored for changes at the molecular level by PKS gene expression. The growth and sporulation processes of A. alternata TEF-1A were affected by Ped. pentosaceus LBM18 in a concentration-dependent manner. Moreover, a significant inhibition of TeA production (74.3%) and the transcription level of the PKS gene (42.9%) was observed. Conclusions: Ped. pentosaceus is one of the promising LAB to be applied as an inoculant for corn silage preservation, aiming to inhibit mycotoxigenic fungi growth and their mycotoxin production.Significance and impact of the study: Ped. pentosaceus could be used as an inoculant to reduce fungal and mycotoxins contamination in grain silage production.
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