Food Bioengineering最新文献

The introduction of heterologous pathways into microorganisms for high-level synthesis of valuable compounds would be extremely meaningful. However, the endogenous heterologous pathway conversion point frequently serves as a bottleneck that limits product synthesis. (+)-Nootkatone is an important functional sesquiterpenoid with a unique grapefruit flavor, which is frequently used as a fragrance. The low catalytic efficiency of the valencene synthase CnVS, the first heterologous enzyme in the biosynthesis of (+)-nootkatone, is the major challenge that restricts the production of (+)-nootkatone in Saccharomyces cerevisiae. In this study, we modified CnVS on the basis of the catalytic environment and mechanism of the enzyme. The residue M560 involving in alkyl transfer during substrate cyclization was found to affect activity. By tuning the residue, mutant M560L exhibited a 60% increase in the unit cell yield of (+)-valencene, which is the precursor of (+)-nootkatone. Furthermore, multistep strategies of metabolic engineering were employed that transferred the metabolic flux to the target product synthesis pathway and displayed the superimposed effect of metabolic and protein engineering on (+)-nootkatone yield. Finally, multicopy integration of tHMG1 and ERG20ERG20-GSG-CnVS^M560L boosted the production of (+)-nootkatone to 85.43 mg/L in flask and 804.96 mg/L (5.29 mg/[L h]) in bioreactor. In conclusion, this study presents a paradigm for constructing microbial cell factories using a combination of protein and metabolic engineering in S. cerevisiae.

Camel milk isolates of lactic acid bacteria were characterized to develop defined starter cultures that could be used for the production of standardized Egyptian Rayeb fermented milk. The isolates have shown a wide diversity of Technological characteristics and antimicrobial activity. Interesting isolates were genetically identified at the species level. Two mixed culture starters composed of Lactiplantibacillus plantarum (FFNL146 and FFNL159) and Lactococcus lactis (FFNL1926 and FFNL2005) along with Leuconostoc pseudomesenteroides FFNL2374 were used in the production of Rayeb from camel milk, cow milk, and their mixture and stored for 14 days under refrigeration. Equally mixed camel and cow milk fermented with both starters had the best results of organoleptic attributes and physicochemical properties compared to samples made of camel milk. This is the first study to present two mixed starter cultures for Rayeb manufacturing. The success of these defined starter cultures will potentially enhance the safety and quality of the Rayeb industry in Egypt.

Non/semi-rational engineering strategies can improve the performance of microbial cell factories under the situations of indistinct metabolic regulations and interactions. However, generating positive variants through these strategies is remarkably low. Using traditional screening methods to evaluate the performance of mutants, such as mass spectrometry and chromatography, is low-throughput, slow-detection, and labor-intensive. Specifically, the efficiency of high-throughput screening (HTS) for strain screening could reach even more 10³−10⁶ strains/day, bridging the gap between non/semi-rational engineering strategies and microbial cell factories construction. This review highlights transcription factor (TFs)-based biosensors in the advances in developing synthetic biosensors for HTS. We hope that this review will help take full advantage of valuable TFs to guide the HTS technology and promote its development.

Recently, a novel two-domain alginate lyase (AlyAL01) was cloned from Algibacter sp. and successfully overexpressed in Escherichia coli BL21(DE3). Biochemical analysis showed that the N-terminal carbohydrate-binding module (CBM) of AlyAL01 had no effect on the enzyme activity and product distributions. Therefore, the N-terminal CBM was substituted with CBM3 to confer the designed chimeric protein with the ability to specifically bind to regenerated amorphous cellulose. As anticipated, the designed chimeric protein (CBM3-L1) exhibited a similar enzyme activity. Moreover, it was found that the CBM3-L1 combined the purification and immobilization in one step with high immobilized efficiency of 65.8%. The immobilized enzyme exhibited good storage stability and moderate reusability. The immobilized enzyme could keep 85% activity when incubated at 4°C for 60 days and 70% activity when incubated at 25°C for 30 days. Furthermore, the immobilized CBM3-L1 kept about 50% of its initial activity after being reused five times. Finally, immobilized CBM3-L1 successively produced well-defined alginate oligosaccharides (AOS) with DPs of 2–6 by controlling reaction time. In sum, our current study provided a feasible strategy for well-defined AOS production.

A xyloglucanase gene (RmXEG12B) was cloned from Rhizomucor miehei CAU432 and successfully expressed in Pichia pastoris. The highest xyloglucanase activity of 26,200 U/mL was achieved after 168 h high-cell-density fermentation. The optimal pH and temperature of RmXEG12B were 5.0 and 55°C, respectively. RmXEG12B showed good stability within pH of 3.0–10.0 and was stable up to 50°C. It exhibited the highest specific activity (5989.3 U/mg) towards tamarind xyloglucan. RmXEG12B hydrolyzed apple pomace xyloglucan to produce the partially hydrolyzed apple pomace xyloglucan, which demonstrated a weight average molecular weight of 1.6 × 10⁴ Da and contained three major oligosaccharides with a degree of polymerization of 7–10. This is a strategy for the comprehensive utilization of apple pomace to produce the partially hydrolyzed apple pomace xyloglucan.

A secreted 50-kDa metalloprotease from Serratia marcescens D15 was identified as rice protein hydrolase (SeMPase), which reached the highest proteolytic activity (477.3 U/ml) in basal medium with 1.5% rice protein (RP) at 35°C and 150 rpm for 48 h. SeMPase exhibited a highest catalytic number for RP (275.8 min⁻¹, K_cat), which contained a highly conserved Zn²⁺-binding (HEIGH) domain, Met-turn (SLMSY), and Ca²⁺ binding domain (GGAGND). RP hydrolysates that prepared by SeMPase showed the highest content of oligopeptides at 72.3%, compared to 64.1% from neutrase, 63.0% from alcalase, 50.2% from trypsin, 47.1% from flavourzyme, and 2.41% from pepsin. Our results showed that cleavage sites of SeMPase exposed in RP are more than those of other proteases because both SeMPase cleavage sites and the amino acid composition of RP are rich in Leu, Val, Phe, Glu, and Ala. SeMPase has significant specificity for the preparation of oligopeptide-enriched RP hydrolysates, which provides a new and highly valued option for industrial preparation of oligopeptide-enriched protein hydrolysates.

Microalgae are widely used in the field of food bioengineering. There are relatively few studies on the synthesis of intracellular electron carriers in microalgae and their related metabolic effects. In this study, overexpression of Geranyl diphosphate: 4-hydroxybenzoate geranyltransferase (lepgt), and the addition of 4-hydroxybenzoic acid (4-HB) as quinone ring precursor were adopted to regulate intracellular plastoquinone (PQ) and ubiquinone (UQ) levels in model algae Chlamydomonas reinhardtii. Small changes in PQ and UQ contents could regulate cell growth and metabolism. The expression of lepgt in C. reinhardtii significantly reduced the intracellular contents of PQ and UQ by 49.14% and 98.30%, respectively. The expression of lepgt observably reduced the photosystem activity and respiration rate and increased the contents of neutral lipid and starch by 63.68% and 19.42%, respectively. Exogenous low concentration of 4-HB (1 mM) can effectively improve the contents of intracellular electron carriers, promote respiration, slightly reduce photosystem efficiency, and increase the maximum specific growth rate by 16.93%. It decreased the protein and oil contents by 15.48% and 15.10%, as well as changed the composition of long-chain fatty acids. This paper provided a novel strategy for developing microalgal cell factories for future food production by perturbation on electron carriers of green algae.

Cells cultivated in bioreactors offer many possibilities for the production of novel and nutritious food products. Scientific and technological advances in cellular agriculture and processing technologies have allowed for the development of new techniques to utilize in vitro animal cells, plant cells, and microorganisms to mimic the organoleptic and nutritional properties of traditional foods as well as to potentially develop entirely new product classes. This review compiles and discusses the state-of-the-art cellular production and processing systems including 3D printing of customizable cell-cultivated food products. In addition to the technological state-of-the art, this article reviews the nutritional characteristics of cell-cultivated foods, introduces examples of new food products, and compiles economic characteristics and environmental impacts of each production system as assessed through technoeconomic analyses and lifecycle assessments. The factors influencing consumer acceptance of cell-cultivated foods are articulated and the potential implications of these new technologies on traditional agricultural industries and food chains are discussed. Lastly, future research and development trajectories are introduced with suggestions for continued development.

The objective of this study was to investigate the influence of particle size, texture, and gastric viscosity on food gastric disintegration and emptying rates. In vitro dynamic gastric digestion was conducted for carrots using a dynamic gastric simulation model. The changes in the texture of carrots and other foods as indicated by bulk resistance, the percent solids emptied, and the particle size distribution were used as parameters to study disintegration kinetics and emptying patterns. The influence of viscosity on food emptying was studied on both indigestible particles (amberlite beads) and digestible solids (carrots). The results indicated medium-size carrot particles (1.40–2.00 mm) had a greater disintegration and a higher amount of emptying rate when compared to larger (2.00–3.34 mm) and smaller (1.14–1.40 mm) carrot particles. A high correlation exists between the final bulk resistance after 120 min digestion and the amount of solids emptied. Increasing viscosity up to values 8.20 Pa·s improved the particle dispersion for amberlite and carrots and increased rates of solids emptying, while further increase in viscosity hindered emptying of amberlite and carrot solids. The variable emptying rates of both indigestible and digestible solids with viscosity were described with a mathematical model based on particle-emptying coefficient.

Facing the challenge of the ever-increasing world population, we must supply high-quality food in sufficient quantity and in an environmentally friendly and efficient manner. Food bioengineering, as a cross-disciplinary between food science and bioengineering, provides the technical possibility to develop sustainable processes to produce healthy, safe, and nutritional foods. The combination of food sciences and bioengineering has realized the production of a wide variety of foods with enhanced shelf life, functionality, and quality to meet versatile consumer demands. Food bioengineering, or applying bioengineering advances in food processing, will undoubtedly continue to play a significant role in maximally utilizing available raw materials and minimizing their waste-releasing emissions, including carbon dioxide. Research and development in Food Bioengineering have become even more extensive and intensive than ever before.

Food Bioengineering is a new open-access journal providing a global platform for peers with interests and activities spanning the cross-disciplinary disciplines of food science, food engineering, bioengineering, nutrition, and chemical engineering. The platform enables authors and readers to communicate their research on innovative technologies and next-generation ingredient sources for sustainable technology development of food processing.

Food Bioengineering will publish original research and review articles, short communications that describe all aspects of biosynthesis and metabolic engineering for food production, food enzymology, food bioprocess engineering, biomaterials for food packaging, health significance of functional foods, future foods, biosensors for food analysis, food chemical engineering, among other relevant topics.

Food Bioengineering aims to become a leading international journal publishing the highest quality original contributions on the latest developments, where each article will make a clear contribution to further basic and applied knowledge in the innovative technologies and next-generation ingredient sources for healthy and sustainable food developments with bioengineering means. By focusing on these areas of research and encouraging the publication and dissemination of such studies, this journal will promote and enhance research in this scientific and technological discipline. Here is our inaugural issue of Food Bioengineering, including three reviews, one editorial, and six original research articles. This collection encompasses several important topics of our journal, reporting the biomanufacturing of lactoferrin and ergothioneine, the expression and immobilization of enzymes for chitooligosaccharides, and D-tagatose production, the health significance of whole wheat flour diet and lactic acid bacteria, and the application of alternative food processing methods. We welcome manuscript submissions of high-quality, innovative, and cutting-edge