The provision of an adequate and high-quality food supply is a challenging issue due to the continued growth of the population and the reduction of arable land resources. To solve these problems, new and efficient food manufacturing processes need to be developed to meet the needs for healthy and nutritious food. Metabolic engineering of microorganisms is a feasible approach to alleviate this problem due to its efficient biosynthesis. For thousands of years, yeast has been used as a cell factory for manufacturing bread, beer and wine. And the development of synthetic biology expands its ability for synthesis of food ingredients, fuels, pharmaceuticals and chemical products. This mini review focuses on metabolic engineering of yeast cell factories to synthesize compounds that have been used as food ingredients with highlighting four food flavors.
As the second largest production material, starch has important value in textile, food, chemical and other fields. The shortcomings of natural starch can be solved, and its properties can be improved by modifying its structure, developing original properties, or introducing new functions, making it more suitable for certain application requirements. At present, the methods of starch modification mainly include chemical, physical, and enzymatic modification. In comparison with the two traditional modification methods (chemical and physical modification) mentioned above, enzymatic modification has the advantages of mild conditions, high substrate selectivity, and high product safety, and it is the most ideal green modification method. In this paper, we present an overview of the modified starch by enzymatic structure design. The modification process and mechanism for granule starch and gelatinized starch are summarized. Further, the difficulties encountered in starch modification by enzymatic modification were also analyzed. These analyses could pave a way for understanding and broadening the preparation and applications of modified starch, and provide theoretical references for the utilization of amylase in starch modification.
Rational microbial chassis design and engineering for improving production of amino acids have attracted a considerable attention. L-glutamate, L-lysine, L-threonine and L-tryptophan are the main amino acids demanded in the food industry. Systems metabolic engineering and synthetic biology engineering generally are believed as the comprehensive engineering approaches to obtain rationally designed strains and construct high-performance platforms for amino acids. The strategies focus on microbial chassis characterization optimization, precise metabolic engineering such as promoter engineering, modular pathway engineering, transporter engineering, and dynamic switch systems application, and global genome streamline engineering to reduce cell burden. In this review, we summarized the efficient engineering strategies to optimize Corynebacterium glutamicum and Escherichia coli cell factories for improving the production of L-glutamate, L-lysine, L-threonine, and L-tryptophan.
Chitin oligosaccharides (CHOS), high-value-added oligomers linked by N-acetyl-d-glucosamine (GlcNAc, NAG), and a small amount of d-glucosamine (GlcN, GA), have aroused increasing interest due to their excellent biological properties, including antibacterial, anti-inflammatory, and immunoprotective activities, and intestinal regulation. The efficient production and utilization of CHOS with high performance can solve problems from chitin as biowaste. However, the large-scale production of well-defined CHOS has not been fully accomplished due to the limited biotechnology and separation methods, thus impeding the research on their biological functions as well as their accurate applications. In this review, we comprehensively summarize the current preparation methods of CHOS, including the chemical, physical, enzymatic and biosynthetic methods. The advantages and disadvantages of the methods are discussed in terms of efficiency, economy, and environmental effects. Furthermore, the applications of CHOS in the food industry and their contributions to human health based on their excellent bioactivities are expounded. It is hoped that this review will help in providing new insights into the production of CHOS with high precision, and support the application of CHOS in serving the food industry as nutritional supplements or foods for special medical purposes.
Food enzymes are basic components used for food processing. Through catalysis, food enzymes can function as removing allergy, enriching absorbable nutrients, improving food texture, and adjusting flavors. Food enzymes work in various conditions, which brought out the need for engineering these enzymes with harsh environment tolerance and higher catalytic efficiency. Artificial intelligence (AI) has recently provided solutions for structural modeling, finding modification hot spots, and guiding mutations toward specific needs, which greatly benefit enzyme engineering. AI-based tools showed great advantages in cutting down the computational time, enabling higher prediction accuracy, and providing trainable models suited for wide uses. In this review, we describe the functions and uses of food enzymes, as well as their utility limitations. The necessity and advantages of using AI-based tools in enzyme engineering, and the differences between using traditional and AI-based tools are mainly discussed. Few AI-based tools for enzyme engineering were introduced and described their function. The perspective of using AI tools and the future challenges were discussed.
Bioactive peptides are released during the production of fermented dairy, vegetables, fruits, legumes, fish, and meat products. The proteolytic specificity of lactic acid bacteria, Bacillus spp., yeasts, and mold, apart from their ability to synthesize bioactive peptides, plays an important role in the generation of specific bioactive peptides in traditional fermented foods. Controlled fermentation using defined starter strains has been explored for the development of bioactive peptides enriched novel fermented foods with potential functionality. Bioactive peptides enriched foods exert diverse health benefits, such as antioxidant, antihypertensive, antidiabetic, and immunomodulatory effects. Bioactive peptides can be used as alternatives to synthetic compounds due to negligible side effects and high valuation in the nutraceutical and functional food market. However, challenges associated with the identification, quantification, organoleptic properties, and bioavailability of bioactive peptides need to be addressed before exploiting the potential of bioactive peptides in the functional food industry. In the present review, we have discussed the production of bioactive peptides in diverse fermented foods. Structural and sequence specificity of peptides and their effect on the expression of distinct health beneficial effects have been described. The potential of utilizing these bioactive peptides for the development of novel functional fermented foods is discussed. Recent advances in peptide identification, quantification, debittering of peptides, and increasing peptide bioavailability have been explained.
Corynebacterium glutamicum is a microbial production host established in the industry 60 years ago. It is mainly used for production of feed and food amino acids. As C. glutamicum strain development has been cutting edge since its discovery, it has been engineered for production of a plethora of valuable products. This review will focus on recent developments of C. glutamicum strain engineering for biotransformation and fermentation processes towards flavor and fragrance molecules as well as pigments and sweeteners.
The use of abundant and cheap one carbon (C1) feedstocks to produce value-added chemicals is an important approach for achieving carbon neutrality and tackling environmental problems. The conversion of C1 feedstocks to high-value chemicals is dependent on efficient C1 assimilation pathways and microbial chassis adapted for efficient incorporation. Here, we opted to summarize the natural and synthetic C1 assimilation pathways and their key factors for metabolizing C1 feedstock. Accordingly, we discussed the metabolic engineering strategies for enabling the microbial utilization of C1 feedstocks for the bioproduction of value-added chemicals. In addition, we highlighted future perspectives of C1-based biomanufacturing for achieving a low-carbon footprint for the biosynthesis of chemicals.
Problems with food security result from increased population, global warming, and decrease in cultivable land. With the advancements in synthetic biology, microbial synthesis of food is considered to be an efficient alternate approach that could permit quick food biosynthesis in an eco-friendly method. Furthermore, synthetic biology can be assumed to the synthesis of healthy or specially designed food components like proteins, lipids, amino acids and vitamins and widen the consumption of feedstocks, thus offering possible resolutions to high-quality food synthesis. This review describes the impact of synthetic biology for the microbial synthesis of various food ingredients production.
Rudimentary food fermentation can be defined as a spontaneous process of conversion of food components through enzymatic action. A great variety of fermented foods are produced using spontaneous approaches; however, cocoa and coffee represent the most important agricultural commodities on international markets. As a manner to increase the efficiency of these processes, starter cultures have been developed and applied under field conditions. The selection process begins with the recovery of microbial strains from spontaneous fermentation through phenotypic and metabolic traits. Next, mutation-based breeding is used to develop and improve well-adapted starter cultures. With advances in synthetic biology, especially in the last decade, the development of robust cellular fabrications with high fermentative capacity has become easier—largely due to the development of genomic approaches, such as next-generation sequencing techniques, CRISPR-Cas system and bioinformatics tools. This review brings prospects on the use of synthetic biology to design new robust strains for use in cocoa and coffee fermentations, but which can be extended to other rudimentary foods. In addition, metabolic traits and target genes (e.g., UvrA, RecA, GPD1, and GPP2) are proposed as a starting point for the improvement of cocoa and coffee starters. Finally, the regulatory and safety requirements for these food crops are addressed. This review aims to stimulate research on the process of fermentation and the associated synthetic biology tools to produce fermented food efficiently and sustainably.
Globally, microalgae are gaining attention due to their high nutritional value and broad application in the pharmaceutical, nutraceutical, food, cosmetics, bio-fertilizer, and biofuel industries. Microalgal-based foods have been shown a positive impact on human health by acting as antioxidants, antimicrobials, anti-inflammatory agents, and antiviral agents. Scale-up, production cost, and safety issues are the significant challenges in microalgae product commercialization. However, various techniques have been developed to overcome these challenges and to produce microalgae bio-products in a high amount and make them safe for human and animals use. Recently, multiple techniques such as metabolic and genetic engineering have emerged to overcome these limitations. The present review focused on the application of these engineering tools to improve biomass yield and nutrient quality in microalgae. However, these tools are proved to be very effective in enhancing the nutrients in microalgae. Limited success has been achieved to improve the quality at the industrial level.