Enhanced extracellular production of alpha-lactalbumin from Bacillus subtilis through signal peptide and promoter screening

Alpha-lactalbumin(α-LA)is a major whey protein found in breast milk and plays a crucial role in the growth and development of infants.In this study,Bacillus subtilis RIK1285 harboring AprE signal peptide(SP)was selected as the original strain for the production ofα-LA.It was found thatα-LA was identified in the pellet after ultrasonic disruption and centrifugation instead of in the fermentation supernatant.The original strain most likely only producedα-LA intracellular,but not extracellular.To improve the expression and secretion ofα-LA in RIK1285,a library of 173 homologous SPs from the B.subtilis 168 genome was fused with target LALBA gene in the pBE-S vector and expressed extracellularly in RIK1285.SP YjcN was determined to be the best signal peptide.Bands in supernatant were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purified by nickel column to calculate the highest yield signal peptide.In addition,different promoters(P_(aprE),P_(43),and P_(glv))were compared and applied.The results indicated that the strain RIK1285-pBE-P_(glv)-YjcN-LALBA had the highestα-LA yield,reaching 122.04μg/mL.This study demonstrates successful expression and secretion of humanα-LA in B.subtilis and establishes a foundation for simulating breast milk for infant formulas and developing bioengineered milk.

Peanut proteins:Extraction,modifications,and applications:A comprehensive review

As naturally sourced proteins,peanut proteins have garnered significant attention from the food industry,owing to their numerous advantages,such as easy extraction,non-pungency,and high bioavailability.Furthermore,peanut proteins are highly digestible in the gastrointestinal tract and boast a high net protein utilization rate,making them an appealing protein source in food products and a promising alternative to animal protein.In this paper,the recent works on the extraction method,modification method,and application of peanut proteins were reviewed.Both advantages and disadvantages of current extraction and modification were discussed.Recently updated information about peanut protein research was summarized.Based on these,the prospection of peanut proteins research was presented,which may be instructive for future research in this field.Future research is still needed for accessible modification methods to develop the functional properties of peanut proteins.

Trans-cinnamaldehyde inhibits Penicillium italicum by damaging mitochondria and inducing apoptosis mechanisms

Plant-derived essential oils have excellent antifungal effects and can be used for the preservation of fresh foods such as fruits and vegetables, but the detailed mechanism has not been fully elucidated. In this study, we investigated the inhibitory effects of trans-cinnamaldehyde on Penicillium italicum, a common pollution fungus in citrus, and explored the antifungal mechanism of trans-cinnamaldehyde by detecting fungal oxidative damage, mitochondrial metabolism, and cell apoptosis. These results showed that transcinnamaldehyde made the carboxylic acid cycle deregulated by altering the related enzyme activities(succinate dehydrogenase, malate dehydrogenase) and mid product. Moreover, the level of reactive oxygen species rose sharply while the redox level was out of regulation. The mitochondrial membrane potential collapsed, leading to the leakage of cytochrome c, and then triggering the activation of apoptotic protease, which was further confirmed by the significant increase in caspase-3 activity from(3.6 ± 0.6) U to(8.8 ± 1.1) U(P < 0.05). The cytochrome c in mitochondria was detected by confocal Raman microspectroscopy, the characteristic intensity index(I750/I2944) was decreased, indicating that the cytochrome c in mitochondria was reduced and leakage. Besides, the strong negative correlation between Raman intensity and the amount of cytochrome c leakage was established with the correlation coefficient of-0.981 7. This study revealed that destroying the integrity of the mitochondrial membrane, activating the mitochondrial-mediated apoptosis pathway was the in-depth antifungal mechanism of trans-cinnamaldehyde;and Raman spectroscopy technology provided new ideas to study this process with high sensitivity determination of cytochrome c.

Efficient biosynthesis of creatine by whole-cell catalysis from guanidinoacetic acid in Corynebacterium glutamicum

Creatine is a naturally occurring derivative of an amino acid commonly utilized in functional foods and pharmaceuticals.Nevertheless,the current industrial synthesis of creatine relies on chemical processes,which may hinder its utilization in certain applications.Therefore,a biological approach was devised that employs whole-cell biocatalysis in the bacterium Corynebacterium glutamicum,which is considered safe for use in food production,to produce safe-for-consumption creatine.The objective of this study was to identify a guanidinoacetate N-methyltransferase(GAMT)with superior catalytic activity for creatine production.Through employing whole-cell biocatalysis,a gamt gene from Mus caroli(Mcgamt)was cloned and expressed in C.glutamicum ATCC 13032,resulting in a creatine titer of 3.37 g/L.Additionally,the study employed a promoter screening strategy that utilized nine native strong promoters in C.glutamicum to enhance the expression level of GAMT.The highest titer was achieved using the P1676 promoter,reaching 4.14 g/L.The conditions of whole-cell biocatalysis were further optimized,resulting in a creatine titer of 5.42 g/L.This is the first report of successful secretory creatine expression in C.glutamicum,which provides a safer and eco-friendly approach for the industrial production of creatine.

Synergistic antifungal mechanism of effective components from essential oil against Penicillium roqueforti

Essential oil(EO)has significant antifungal activity.However,there is limited information on the mechanism of the synergistic antifungal effect of the effective components of EO against fungi.In the present study,molecular electrostatic potential and molecular docking were used for the first time to investigate the synergistic antifungal mechanism of eugenol and citral small molecule(C_(EC))against Penicillium roqueforti.The results showed that the C_(EC)treatment made the activity ofβ-(1,3)-glucan synthase(GS)and chitin synthase(CS)decreas by 20.2%and 11.1%,respectively,and the contents of which decreased by 85.0%and 27.9%,respectively compared with the control group.Molecular docking revealed that C EC small molecules could bind to GS and CS through different amino acid residues,inhibiting their activity and synthesis.The C EC can combine with tryptophan,tyrosine,and phenylalanine in the cell membrane,causing damage to the cell membrane.The binding sites between small molecules and amino acids were mainly around the OH group.In addition,C EC affected the energy metabolism system and inhibited the glycolysis pathway.Simultaneously,C EC treatment reduced the ergosterol content in the cell membrane by 58.2%compared with the control group.Finally,changes in𝛽-galactosidase,metal ion leakage,and relative conductivity confirmed the destruction of the cell membrane,which resulted in the leakage of cell contents.The above results showed that C EC can kill P.roqueforti by inhibiting energy metabolism and destroying the integrity of the cell membrane.

Marination ingredients on meat quality and safety—a review

The practice of utilizing various categories of ingredients for marination has been prevalent in both home cooking and the meat industry for an extended period.Meat and meat products treated with various marination ingredients either alone or in combination with multiple marination processes can enhance color,flavor,and tenderness,while also improving their shelf life by reducing the growth of pathogenic microorganisms and lipid oxidation.This narrative review aims to examine all recent scientific literature on various meat and meat products subjected to marination.Through Google Scholar,PubMed,and Web of Science,the review summarizes all recent marinated and marination research articles,including types of marination ingredients,marination method,marinade mechanism,effect on sensory and nutritional quality,safety,shelf life,and health implications,resulting in a comprehensive overview of all information under marinades and marination for all scientists and food sectors concerned.The highlighted information will indicate future directions for the development of marination ingredients in the meat industry.