Lignocellulosic biomass is a most promising feedstock in the production of second-generation biofuels. Efficient degradation of lignocellulosic biomass requires a synergistic action of several ...cellulases and hemicellulases. Cellulases depolymerize cellulose, the main polymer of the lignocellulosic biomass, to its building blocks. The production of cellulase cocktails has been widely explored, however, there are still some main challenges that enzymes need to overcome in order to develop a sustainable production of bioethanol. The main challenges include low activity, product inhibition, and the need to perform fine-tuning of a cellulase cocktail for each type of biomass. Protein engineering and directed evolution are powerful technologies to improve enzyme properties such as increased activity, decreased product inhibition, increased thermal stability, improved performance in non-conventional media, and pH stability, which will lead to a production of more efficient cocktails. In this review, we focus on recent advances in cellulase cocktail production, its current challenges, protein engineering as an efficient strategy to engineer cellulases, and our view on future prospects in the generation of tailored cellulases for biofuel production.
Intracellular lipids are sensitive to freezing. Lipidome modification is an important tool for studying the role of intracellular lipids in cryotolerance of mammalian oocytes and preimplantation ...embryos.
To study the effects of in vitro exposure of murine embryos to saturated stearic acid (SA) on the lipid content, embryo development and cryotolerance.
In vivo derived mouse embryos were cultured with 100 uM SA for 48 h up to the morula/blastocyst stage. Some of the SA-treated embryos were chosen for the evaluation of their development competence and the change in the lipidome, and other embryos were either slowly frozen or rapidly vitrified.
Nile red staining combined with confocal laser scanning microscopy revealed a decrease in the total amount of lipids in the SA-treated embryos. Raman measurements showed that the lipid unsaturation was lower in embryos after in vitro SA culture. The addition of SA did not affect the embryo development before cryopreservation, but negatively affected the results of slow freezing cryopreservation and vitrification.
In vitro SA exposure lowered the total amount of intracellular lipids and unsaturation in mouse embryos. The changes were accompanied with a significantly lower efficacy of embryo cryopreservation. https://doi.org/10.54680/fr24110110512.
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•Protein surface engineering was performed to improve the enzyme properties.•Half-life time was improved in 1.3–1.6 times at 70 °C and 1.2–1.4 times at 80 °C.•Residual activity after ...72 h incubation in BmimCl was increased in 1.7–1.9 times.•The effectiveness of pretreated biomass hydrolysis was increased in 1.1–1.2 times.
Thermostability and stability in ionic liquids are essential properties of cellulases that are applied in industrial processes of bioconversion. Engineering of protein surface of endoglucanase II from Penicillium verruculosum was used to improve the enzyme thermostability and stability in 1-butyl-3-methylimidazolium chloride (BmimCl). The engineering was based on analysis of the protein surface topography and enhanced by multiple sequence alignment and ΔΔG calculations. In the case of the thermostability, half-life time was improved in 1.3–1.6 times at 70 °C and 1.2–1.4 times at 80 °C. In the case of the stability in BmimCl, the residual activity after 72 h of incubation in the presence of BmimCl (50 g/L, 50 °C, pH 4.5) was 1.7–1.9 times greater for the tailored enzyme. The yield of reducing sugars after enzymatic hydrolysis of aspen wood pretreated with BmimCl was 10–20% higher with the tailored endoglucanase.
We report pronounced and specific antiglioblastoma cell phototoxicity of 5 nm TiO2 particles covalently tethered to an antibody via a dihydroxybenzene bivalent linker. The linker application enables ...absorption of a visible part of the solar spectrum by the nanobio hybrid. The phototoxicity is mediated by reactive oxygen species (ROS) that initiate programmed death of the cancer cell. Synchrotron X-ray fluorescence microscopy (XFM) was applied for direct visualization of the nanobioconjugate distribution through a single brain cancer cell at the submicrometer scale.
Defects induced by liquid-phase exfoliation of graphite using sonication were studied. It was shown that localized impact by cavitation shock waves can produce bulk ripplocations and various types of ...dislocations in graphite nanoplatelets. Formation of ripples is more pronounced in large aspect (length/width) ratio platelets or nanobelts. Quasi-periodical ripple systems were observed in many nanobelts after sonication. Mechanism of formation of ripples and dislocations during sonication was proposed. Surprisingly, fast high-temperature processing was found to anneal most of defects. This is consistent with our observations that defects associated with ripplocations are strongly localized and thus can be fast annealed.
About ten years have passed since the last published report in Russian on the speciation and distribution features of radionuclides in the bottom sediment of Production Association (PA) “Mayak” ...(further mentioned as Mayak) artificial reservoirs. Herein, the desorption parameters of 137Cs, 90Sr, 241Am, and 238,239+240Pu and their association with bottom sediment components were investigated in two Mayak reservoirs (R-17 (decommissioned) and R-4 (still in use) with big differences in size, activity and water regime). It was established that 137Cs and 90Sr desorption from the R-17 bottom sediment reach constant values after 24 h, and the desorption degree is not dependant on pH but on ionic strength. Sequential extraction indicated that the main accumulation mechanism of 137Cs is incorporation into the clay minerals. The maximum plutonium content was detected in the residual fraction of the R-17 bottom sediment, which could be associated with the effects of precipitation aging. In R-4, plutonium is equally distributed between residual and bound to organic matter fractions. The 241Am is associated with carbonates in the R-17 bottom sediment and with organic matter in the R-4 bottom sediment and to lesser extent with iron-manganese oxides. The radionuclides are becoming less environmentally available with time since deposition.
•The radionuclides species in the lakes bottom sediments (same climatic conditions and source of radionuclides) are different.•Sorption mechanisms of Cs, Am, and Pu in bottom sediments from Plant “Mayak” reservoirs were identified.•The radionuclides are becoming less environmentally available with time since deposition.
This study provides computational‐assisted engineering of the cellobiohydrolase I (CBH‐I) from Penicillium verruculosum with simultaneous enhanced thermostability and tolerance in ionic liquids, deep ...eutectic solvent, and concentrated seawater without affecting its wild‐type activity. Engineered triple variant CBH‐I R1 (A65R‐G415R‐S181F) showed 2.48‐fold higher thermostability in terms of relative activity at 65°C after 1 h of incubation when compared with CBH‐I wild type. CBH‐I R1 exhibited 1.87‐fold, 1.36‐fold, and 1.57‐fold higher specific activities compared with CBH‐I wild type in BmimCl (50 g/L), ChCl (50 g/L), and two‐fold concentrated seawater, respectively. In the multicellulases mixture, CBH‐I R1 showed higher hydrolytic efficiency to hydrolyze aspen wood compared with CBH‐I wild type in the buffer, BmimCl (50 g/L), and two‐fold concentrated seawater, respectively. Structural analysis revealed a molecular basis for the higher stability of the CBH‐I structure in which A65R and G415R substitutions form salt bridges (D64 … R65, E411 … R415) and S181F forms π–π interaction (Y155 … F181), leading to stabilize surface‐exposed flexible α‐helixes and loop in the multidomain β‐jelly roll fold structure, respectively. In conclusion, the variant CBH‐I R1 could enable efficient lignocellulosic biomass degradation as a cost‐effective alternative for the sustainable production of biofuels and value‐added chemicals.
The efficiency of cellobiohydrolase I (CBH‐I) is highly essential for the sustainable hydrolysis of lignocellulosic biomass. Pramanik et al. provided an engineered variant CBH‐I R1, which offers a great potential for enzymatic lignocellulosic biomass degradation as a cost‐effective alternative to produce sustainable energy and value‐added chemicals.
The concentration and sorption behavior of
Np on the bottom sediments of water bodies in the Far East region of Russia (Lake Khanka and Peter the Great Bay) were studied for the first time. The
Np ...concentrations vary from 1.06 × 10
to 4.43 × 10
mBq g
in the bottom sediments of Lake Khanka and from 1.05 × 10
to 2.52 × 10
mBq g
for Amur Bay. The experiment on the adsorption of Np on marine and lake sediment showed that it is sorbed through complexation with silicates (albite, leucite). The Np sorption isotherm on marine sediments is described by the Langmuir equation; the distribution coefficients (Kd) of Np vary from 57 to 588 mL g
. For lake sediments, the isotherm is described by the Henry equation; the Kd value reaches 935 mL g
.
The role of plasma cholesterol in impairing arterial function and elasticity remains unclear. We evaluated arterial stiffness, measured locally in the common carotid artery by high-resolution ...echo-tracking, and aortic stiffness, using carotid-femoral pulse wave velocity (PWV) (the "gold-standard" measurement of arterial stiffness), in treatment-naive patients with heterozygous familial hypercholesterolemia (FH).
The study included 66 patients with FH (10-66 years old) and 57 first-degree relatives without FH (11-61 years old). Carotid-femoral PWV was determined by SphygmoCor (AtCor, Australia). The parameters of carotid stiffness β-index, Peterson elastic modulus and local PWV were assessed with regard to the common carotid artery at a distance of 1cm from the bifurcation (AlokaProsound Alpha7, Japan).
FH patients showed significantly higher β-index (6.3(4.8-8.2) vs. 5.2(4.2-6.4), p = 0.005), Ep (78(53-111) kPa vs. 62(48-79) kPa, p = 0.006), local PWV (5.4(4.5-6.4) m/c vs. 4.7(4.2-5.4) m/c, p = 0.005), but comparable values of carotid-femoral PWV (6.76(7.0-7.92) m/c vs. 6.48(6.16-7.12) m/c, p = 0.138). Carotid arteries and the aorta stiffened with age in patients with FH, but after 30 years, carotid arteries stiffened more significantly than the aorta.
Our study demonstrated that treatment-naive patients with FH had stiffer carotid arteries than their relatives, but showed no difference in aortic stiffness. We also found out that the rate of reduction of elasticity of the aorta and carotid arteries in FH patients varies: it is observed earlier in carotid arteries than in the aorta.
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