Projected environmental benefits of replacing beef with microbial protein

Neurospora intermedia from a traditional fermented food enables waste-to-food conversion

Fungal fermentation of food and agricultural by-products holds promise for improving food sustainability and security. However, the molecular basis of fungal waste-to-food upcycling remains poorly understood. Here we use a multi-omics approach to characterize oncom, a fermented food traditionally produced from soymilk by-products in Java, Indonesia. Metagenomic sequencing of samples from small-scale producers in Western Java indicated that the fungus Neurospora intermedia dominates oncom. Further transcriptomic, metabolomic and phylogenomic analysis revealed that oncom-derived N. intermedia utilizes pectin and cellulose degradation during fermentation and belongs to a genetically distinct subpopulation associated with human-generated by-products. Finally, we found that N. intermedia grew on diverse by-products such as fruit and vegetable pomace and plant-based milk waste, did not encode mycotoxins, and could create foods that were positively perceived by consumers outside Indonesia. These results showcase the traditional significance and future potential of fungal fermentation for creating delicious and nutritious foods from readily available by-products.

Enhanced mycelium biomass and polysaccharide production in genetically modified Pleurotus ostreatus using agricultural wastes

Edible fungi, healthier for humans and sustainable for the planet, attract unprecedented attention. In the study, the genetically modified Pleurotus ostreatus overexpression phosphoglucomutase (PGM) was constructed. P. ostreatus overexpression PGM (Po::PGM) had 4.96-folds higher expression level of PGM. Po::PGM grew thicker mycelium and more mycelium branches. Additional Ca2+ can inhibit mycelium growth, and cyclic adenosine monophosphate completely inhibited their growth of Po::PGM. Secondly, Overexpression of PGM made P. ostreatus become more sensitive to cell wall disruptors, and caused 12.75 % reduction of β-1, 3-glucan and 40.53 % increase of chitin in cell wall. In submerged fermentation, the mycelia biomass yield and endopolysaccharide (IPS) production of Po::PGM in basic PDB can reach 11.18 g/l and 2.55 g/l, increasing by 20.86 % and 28.79 %, respectively. Whereas exopolysaccharide (EPS) reduced by 3.28 %. After replacing potato and glucose in PDB by wheat bran, mycelia biomass and EPS production of Po::PGM were all improved. The additional lactose in wheat bran did not only furtherly enhance mycelia biomass yield of Po::PGM to 27.78 g/l by 199.03 %, but IPS production also increased by 277.99 % to 6.07 g/l. The results provided us key ideas and important research directions that at least manipulating the PGM gene could obtain high-efficient use of agricultural wastes producing more fungus-based foods.

Health or environment? Understanding which informative message is more effective in replacing red meat with mushroom-based alternatives

Current concerns regarding the health and environmental consequences associated with excessive meat consumption have underscored the importance of guiding consumers towards more sustainable diets. Given this perspective, this study seeks to evaluate the effectiveness of tailored informative messages in shaping consumer behaviour, particularly within the framework of replacing meat with mushroom-based alternatives. Additionally, it explores the factors influencing informative message effectiveness. An experimental online survey was conducted on a sample of 951 Italian consumers. Specifically, the sample was divided into three groups, of which 309 individuals formed the control group, 311 participants received informative messages on the health risks associated with red meat consumption, and 331 participants received informative messages emphasizing the environmental damages linked to red meat consumption. In both treatments, there was support for mushroom-based alternatives. Analyses included subgroup assessments, tests to verify treatments effectiveness, along with OLS regression to pinpoint variables influencing message effectiveness. The results underscore a fair positive impact of the two informative messages (mean scores: 8.75 for health message; 7.01 for environmental message). Noteworthy psychosocial variables, including lifestyle patterns, nutritional perceptions, and ecological attitudes, emerged as determinants in shaping consumers' food choices. While health-related messages exhibit marked influence, the nuanced landscape of diverse drivers and barriers necessitates judicious communication strategies. These insights bear significance for policymakers, health professionals, and marketers, offering guidance for interventions that effectively influence consumer behaviour toward more sustainable and healthier food practices.

Single cell protein production from methane in a gas-delivery membrane bioreactor

Single cell protein (SCP, or microbial protein) is one of the emerging alternative protein sources to address the global challenge of food insecurity. Recently, the SCP produced from methane has attracted substantial attention since methane is a renewable resource attainable from anaerobic digestion. However, the supply of methane, an insoluble gas in water, is one of the major challenges in producing methane-based SCP. This work developed a novel bioreactor configuration, in which hollow fiber membrane was used for efficient methane supply while microorganisms were growing in the suspended form favourable for the biomass harvest. Over a 312-day operation, the impacts of three critical parameters on the SCP production were investigated, including the ratio of methane loading to ammonium loading, the ratio of methane loading to oxygen loading, and the sludge retention time (SRT). Under the condition of 4 g CH4/g NH4+, 4 g O2/g CH4, and SRT of 4 days, the highest SCP production yield was observed and determined to be 1.36 g SCP/g CH4 and 5.05 g SCP/g N, respectively. The protein content was up to 67 %, which is higher than the majority of reported values to date. Moreover, the methane and ammonium utilization efficiencies were both close to 100 %, suggesting the highly efficient utilization of substrates in this new bioreactor configuration. A high relative abundance of essential amino acids (EAA) above 42 % was achieved, representing the highest EAA content reported. These findings provide valuable insights into SCP production using methane as a feedstock.

Knowledge Maps and Emerging Trends in Cell-Cultured Meat since the 21st Century Research: Based on Different National Perspectives of Spatial-Temporal Analysis

Cell-cultured meat holds significant environmental value as an alternative protein source. Throughout the 21st century, cell-cultured meat has progressively penetrated commercial markets. However, a systematic review encompassing the entire field needs improvement. Employing Citespace, Vosviewer, and R-Bibliometrix software, a bibliometric analysis was used to present the research progress and general development trends of 484 articles on cell-cultured meat from 2000 to 2022 based on countries, authors, institutions, and keywords. This analysis provides ideas for the future development of cell-cultured meat in different countries or regions worldwide. Research on cell-cultured meat from 2000 to 2022 has undergone two phases: fluctuating growth (2000-2013) and rapid growth (2013-2022). Noteworthy contributions to cell-cultured meat studies emerge from author groups in the United States of America, the United Kingdom, and China, with influential institutions like the University of Bath significantly impacting pertinent research. Furthermore, over the past two decades, research has leaned towards exploring topics such as "biomaterials", "cultured", "land use", "public opinion", "animal welfare", and "food safety". Furthermore, this study reveals differences in nomenclature between regions and institutions. "Cultured meat" is more popular in some countries than in other forms. Institutions in Asia use "cultured meat" more frequently; however, institutions in the Americas adopt "cultivated meat" and rarely adopt "in vitro meat", and institutions in the European region have no particularly prominent tendency towards a specific nomenclature. Future research should emphasize aligning the labeling of cell-cultured meat with effective management strategies and referencing regulatory policies across various countries. For the first time, we use three different bibliometric methods to analyze temporal and spatial variation in research on cellular meat. The results of this study have a multiplier effect. We provide a theoretical basis and a practical reference for the identification of alternatives in the dual context of "food crisis and food security" and "climate crisis". At the same time, we also provide a reference for the sustainable development of the food system.

Protein transition: focus on protein quality in sustainable alternative sources

The current consumption trends, combined with the expected demographic growth in the coming years, call for a protein transition, i.e., the partial substitution of animal protein-rich foods with foods rich in proteins produced in a more sustainable way. Here, we have discussed some of the most common and promising protein sources alternative to animal proteins, namely: legumes, insects, and microorganisms (including microalgae and fungi). The primary objective was to assess their nutritional quality through the collection of digestible indispensable amino acid score (DIAAS) values available in the scientific literature. Protein digestibility corrected amino acid score (PDCAAS) values have been used where DIAAS values were not available. The ecological impact of each protein source, its nutritional quality and the potential applications in traditional foods or novel food concepts like meat analogues are also discussed. The data collected show that DIAAS values for animal proteins are higher than all the other protein sources. Soybean proteins, mycoproteins and proteins of some insects present relatively high DIAAS (or PDCAAS) values and must be considered proteins of good quality. This review also highlights the lack of DIAAS values for many potentially promising protein sources and the variability induced by the way the proteins are processed.

The Next Food Revolution Is Here: Recombinant Microbial Production of Milk and Egg Proteins by Precision Fermentation

Animal-based agriculture and the production of protein-rich foods from animals, particularly from ruminants, are not sustainable and have serious climate effects. A new type of alternative proteins is now on the menu, namely animal proteins produced recombinantly by microbial fermentation. This new technology, precision fermentation, is projected to completely disrupt traditional animal-based agriculture. Certain milk and egg proteins along with specific meat substitute analog components produced by precision fermentation are already entering the market. This first wave of precision fermentation products targets the use of these proteins as protein additives, and several commercial players are already active in the field. The cost-efficiency requirements involve production titers above 50 g/L which are several orders of magnitude higher than those for pharmaceutical protein manufacture, making strain engineering, process optimization, and scale-up critical success factors. This new development within alternative proteins defines a new research direction integrating biotechnology, process engineering, and sustainable food protein production.

Current trends and possibilities of typical microbial protein production approaches: a review

Global population growth and demographic restructuring are driving the food and agriculture sectors to provide greater quantities and varieties of food, of which protein resources are particularly important. Traditional animal-source proteins are becoming increasingly difficult to meet the demand of the current consumer market, and the search for alternative protein sources is urgent. Microbial proteins are biomass obtained from nonpathogenic single-celled organisms, such as bacteria, fungi, and microalgae. They contain large amounts of proteins and essential amino acids as well as a variety of other nutritive substances, which are considered to be promising sustainable alternatives to traditional proteins. In this review, typical approaches to microbial protein synthesis processes were highlighted and the characteristics and applications of different types of microbial proteins were described. Bacteria, fungi, and microalgae can be individually or co-cultured to obtain protein-rich biomass using starch-based raw materials, organic wastes, and one-carbon compounds as fermentation substrates. Microbial proteins have been gradually used in practical applications as foods, nutritional supplements, flavor modifiers, and animal feeds. However, further development and application of microbial proteins require more advanced biotechnological support, screening of good strains, and safety considerations. This review contributes to accelerating the practical application of microbial proteins as a promising alternative protein resource and provides a sustainable solution to the food crisis facing the world.

Edible mycelium bioengineered for enhanced nutritional value and sensory appeal using a modular synthetic biology toolkit

Filamentous fungi are critical in the transition to a more sustainable food system. While genetic modification of these organisms has promise for enhancing the nutritional value, sensory appeal, and scalability of fungal foods, genetic tools and demonstrated use cases for bioengineered food production by edible strains are lacking. Here, we develop a modular synthetic biology toolkit for Aspergillus oryzae, an edible fungus used in fermented foods, protein production, and meat alternatives. Our toolkit includes a CRISPR-Cas9 method for gene integration, neutral loci, and tunable promoters. We use these tools to elevate intracellular levels of the nutraceutical ergothioneine and the flavor-and color molecule heme in the edible biomass. The strain overproducing heme is red in color and is readily formulated into imitation meat patties with minimal processing. These findings highlight the promise of synthetic biology to enhance fungal foods and provide useful genetic tools for applications in food production and beyond.

Designing sustainable circular bioeconomy solutions for the pulse industry: The case of crude pea starch as a substrate for single cell protein production

Valorization of crude pea starch has become a key focus in the pea industry's sustainability pursuit. This study aimed to explore the circularity potential of crude pea starch as a nutrient-dense substrate for the solid-state cultivation of yeast (Saccharomyces cerevisiae) Single Cell Protein (SCP). Following the ISO 2006:14040/44 standard, a life cycle assessment (LCA) was performed to ascertain the environmental performance and operational dynamics of baseline and scenario pea starch-based yeast SCP process designs and identify optimal design considerations. Results demonstrated a higher relative contribution to the toxicity categories, with a relatively less contribution to global warming and land use. The distribution and media enrichment processes were identified as the hotspots, contributing about 32-55 % and 40-56 % to global warming and land use, respectively. Generally, train and air freight were more sustainable than lorry freight, respective of mileage and mass. Regarding system alteration, eliminating the media enrichment process could offset about 26 % of land footprint, with a similar trend for most impact categories. Process benchmarking showed up to a 3-fold reduction in global warming impacts relative to soybean meal, and about 71 % offset relative to fishmeal. Consequential LCA showed a general sustainability preference for substituting the aquacultural feeds with pea starch-based SCP, with a stronger emphasis on fishmeal substitution. Overall, these findings highlight the potential of the proposed SCP design as a sustainable upcycling solution with substitutionary potentials for conventional food and feeds, recommending further exploration in value and wealth creation.

Mycelium: A Nutrient-Dense Food To Help Address World Hunger, Promote Health, and Support a Regenerative Food System

There is a need for transformational innovation within the existing food system to achieve United Nations Sustainable Development Goal 2 of ending hunger within a sustainable agricultural system by 2030. Mycelium, the vegetative growth form of filamentous fungi, may represent a convergence of several features crucial for the development of food products that are nutritious, desirable, scalable, affordable, and environmentally sustainable. Mycelium has gained interest as technology advances demonstrate its ability to provide scalable biomass for food production delivering good flavor and quality protein, fiber, and essential micronutrients urgently needed to improve public health. We review the potential of mycelium as an environmentally sustainable food to address malnutrition and undernutrition, driven by food insecurity and caloric dense diets with less than optimal macro- and micronutrient density.

Fermented foods, their microbiome and its potential in boosting human health

Fermented foods (FFs) are part of the cultural heritage of several populations, and their production dates back 8000 years. Over the last ~150 years, the microbial consortia of many of the most widespread FFs have been characterised, leading in some instances to the standardisation of their production. Nevertheless, limited knowledge exists about the microbial communities of local and traditional FFs and their possible effects on human health. Recent findings suggest they might be a valuable source of novel probiotic strains, enriched in nutrients and highly sustainable for the environment. Despite the increasing number of observational studies and randomised controlled trials, it still remains unclear whether and how regular FF consumption is linked with health outcomes and enrichment of the gut microbiome in health-associated species. This review aims to sum up the knowledge about traditional FFs and their associated microbiomes, outlining the role of fermentation with respect to boosting nutritional profiles and attempting to establish a link between FF consumption and health-beneficial outcomes.

Efficient Mycoprotein Production with Low CO2 Emissions through Metabolic Engineering and Fermentation Optimization of Fusarium venenatum

The global protein shortage is intensifying, and promising means to ensure daily protein supply are desperately needed. The mycoprotein produced by Fusarium venenatum is a good alternative to animal/plant-derived protein. To comprehensively improve the mycoprotein synthesis, a stepwise strategy by blocking the byproduct ethanol synthesis and the gluconeogenesis pathway and by optimizing the fermentation medium was herein employed. Ultimately, compared to the wild-type strain, the synthesis rate, carbon conversion ratio, and protein content of mycoprotein produced from the engineered strain were increased by 57% (0.212 vs 0.135 g/L·h), 62% (0.351 vs 0.217 g/g), and 57% (61.9 vs 39.4%), respectively, accompanied by significant reductions in CO2 emissions. These results provide a referential strategy that could be useful for improving mycoprotein synthesis in other fungi; more importantly, the obtained high-mycoprotein-producing strain has the potential to promote the development of the edible protein industry and compensate for the gap in protein resources.

Diets intervene osteoporosis via gut-bone axis

Osteoporosis is a systemic skeletal disease that seriously endangers the health of middle-aged and older adults. Recently, with the continuous deepening of research, an increasing number of studies have revealed gut microbiota as a potential target for osteoporosis, and the research concept of the gut-bone axis has gradually emerged. Additionally, the intake of dietary nutrients and the adoption of dietary patterns may affect the gut microbiota, and alterations in the gut microbiota might also influence the metabolic status of the host, thus adjusting bone metabolism. Based on the gut-bone axis, dietary intake can also participate in the modulation of bone metabolism by altering abundance, diversity, and composition of gut microbiota. Herein, combined with emerging literatures and relevant studies, this review is aimed to summarize the impacts of different dietary components and patterns on osteoporosis by acting on gut microbiota, as well as underlying mechanisms and proper dietary recommendations.

Nutritional Values and Bio-Functional Properties of Fungal Proteins: Applications in Foods as a Sustainable Source

From the preparation of bread, cheese, beer, and condiments to vegetarian meat products, fungi play a leading role in the food fermentation industry. With the shortage of global protein resources and the decrease in cultivated land, fungal protein has received much attention for its sustainability. Fungi are high in protein, rich in amino acids, low in fat, and almost cholesterol-free. These properties mean they could be used as a promising supplement for animal and plant proteins. The selection of strains and the fermentation process dominate the flavor and quality of fungal-protein-based products. In terms of function, fungal proteins exhibit better digestive properties, can regulate blood lipid and cholesterol levels, improve immunity, and promote gut health. However, consumer acceptance of fungal proteins is low due to their flavor and safety. Thus, this review puts forward prospects in terms of these issues.

Three decades of shade trees improve soil organic carbon pools but not methane uptake in coffee systems

The rapid expansion of coffee plantations in tropical area at the cost of natural forest may suppress the methane (CH4) uptake and change the soil fertility. However, observations on soil CH4 uptake rates and the ecological consequence studies on coffee-based plantations are sparse. The objectives of this study were to characterize the dynamics of CH4 uptake among natural forest, coffee monoculture (CM), and coffee intercropping with shade tree (CI), and to evaluate the key drivers of soil CH4 uptake. Results showed that the conversion of forest into 25-year and 34-year CM plantations significantly reduced the soil organic carbon (SOC) content by 57% and 76%, respectively, whereas CI plantation profoundly increased the SOC by 20%-76% compared with CM plantation. Although soils of forest, CM and CI functioned exclusively as CH4 sinks, the CM and CI plantations significantly decreased the ambient CH4 uptake rates by 64%-83% due to soil moisture shift and soil nitrate availability by using chemical fertilizer. Interestingly, the potential CH4 uptake of CM and CI plantations did not decrease and in some treatments, was even higher than that of the natural forest. Potential CH4 uptake showed a negative correlation with soil pH and SOC content, but a positive correlation with soil available phosphorus (AP). Collectively, although the SOC and soil pH were increased through intercropping with shade trees for decades, the inhibition of atmospheric CH4 uptake was still difficult to alleviate.

The potential of CO2-based production cycles in biotechnology to fight the climate crisis

Rising CO2 emissions have pushed scientists to develop new technologies for a more sustainable bio-based economy. Microbial conversion of CO2 and CO2-derived carbon substrates into valuable compounds can contribute to carbon neutrality and sustainability. Here, we discuss the potential of C1 carbon sources as raw materials to produce energy, materials, and food and feed using microbial cell factories. We provide an overview of potential microbes, natural and synthetic C1 utilization pathways, and compare their metabolic driving forces. Finally, we sketch a future in which C1 substrates replace traditional feedstocks and we evaluate the costs associated with such an endeavor.

The transcription factor GCN4 contributes to maintaining intracellular amino acid contents under nitrogen-limiting conditions in the mushroom Ganoderma lucidum

BACKGROUND

Edible mushrooms are delicious in flavour and rich in high-quality protein and amino acids required by humans. A transcription factor, general control nonderepressible 4 (GCN4), can regulate the expression of genes involved in amino acid metabolism in yeast and mammals. A previous study revealed that GCN4 plays a pivotal role in nitrogen utilization and growth in Ganoderma lucidum. However, its regulation is nearly unknown in mushrooms.

RESULTS

In this study, we found that the amino acid contents reached 120.51 mg per gram of mycelia in the WT strain under 60 mM asparagine (Asn) conditions, but decreased by 62.96% under 3 mM Asn conditions. Second, silencing of gcn4 resulted in a 54.2% decrease in amino acid contents under 60 mM Asn, especially for the essential and monosodium glutamate-like flavour amino acids. However, these effects were more pronounced under 3 mM Asn. Third, silencing of gcn4 markedly inhibited the expression of amino acid biosynthesis and transport genes. In addition, GCN4 enhanced the tricarboxylic acid cycle (TCA) and glycolytic pathway and inhibited the activity of target of rapamycin complex 1 (TORC1), thus being beneficial for maintaining amino acid homeostasis.

CONCLUSION

This study confirmed that GCN4 contributes to maintaining the amino acid contents in mushrooms under low concentrations of nitrogen. In conclusion, our study provides a research basis for GCN4 to regulate amino acid synthesis and improve the nutrient contents of edible mushrooms.

Feeding climate and biodiversity goals with novel plant-based meat and milk alternatives

Plant-based animal product alternatives are increasingly promoted to achieve more sustainable diets. Here, we use a global economic land use model to assess the food system-wide impacts of a global dietary shift towards these alternatives. We find a substantial reduction in the global environmental impacts by 2050 if globally 50% of the main animal products (pork, chicken, beef and milk) are substituted-net reduction of forest and natural land is almost fully halted and agriculture and land use GHG emissions decline by 31% in 2050 compared to 2020. If spared agricultural land within forest ecosystems is restored to forest, climate benefits could double, reaching 92% of the previously estimated land sector mitigation potential. Furthermore, the restored area could contribute to 13-25% of the estimated global land restoration needs under target 2 from the Kunming Montreal Global Biodiversity Framework by 2030, and future declines in ecosystem integrity by 2050 would be more than halved. The distribution of these impacts varies across regions-the main impacts on agricultural input use are in China and on environmental outcomes in Sub-Saharan Africa and South America. While beef replacement provides the largest impacts, substituting multiple products is synergistic.

Sustainability Perception of Italian Consumers: Is it Possible to Replace Meat, and What Is the Best Alternative?

Growing worldwide food demand with its environmental impacts requires a reshaping of food consumption. This study aims to evaluate the degree of Italian consumers' awareness of sustainability and whether protein alternatives to meat could be accepted. A cross-sectional survey was carried out on a group of 815 respondents, representative of the Italian adult population for geography, gender, and age, using multivariate analysis together with cluster analysis. Lack of awareness of the consequences of food choices on the environment was found in 45% of respondents, and 51% reduced their consumption of meat. Typical foods of the Mediterranean diet (84% legumes 82% eggs, and 77% fish) were selected as the preferred sources of protein to replace meat, while insects and insect-based products were less accepted (67%). The importance of meat is the latent factor that explains more than 50% of the common variance observed in the factor analysis. The cluster analysis confirmed the importance of meat for Italian consumers, emphasizing other aspects of the sustainability of food choices. Cluster 1 (25.6%) considered meat very important. Two out of five clusters (clusters 2 and 3, 38%) considered meat replaceable in the diet, and cluster 4 (31.3%) included meat consumers that were willing to be sustainable. Cluster 5 identifies the "unsustainable consumers" (5.7%). In conclusion, besides the perceived importance of meat, there is room for recommendations for its reduction by proposing alternative foods already present in the Mediterranean diet.

Environmental and nutritional Life Cycle Assessment of novel foods in meals as transformative food for the future

Sustainable diets are key for mitigating further anthropogenic climate change and meeting future health and sustainability goals globally. Given that current diets need to change significantly, novel/future foods (e.g., insect meal, cultured meat, microalgae, mycoprotein) present options for protein alternatives in future diets with lower total environmental impacts than animal source foods. Comparisons at the more concrete meal level would help consumers better understand the scale of environmental impacts of single meals and substitutability of animal sourced foods with novel foods. Our aim was to compare the environmental impacts of meals including novel/future foods with those of vegan and omnivore meals. We compiled a database on environmental impacts and nutrient composition of novel/future foods and modeled the impacts of calorically similar meals. Additionally, we applied two nutritional Life Cycle Assessment (nLCA) methods to compare the meals in terms of nutritional content and environmental impacts in one index. All meals with novel/future foods had up to 88 % less Global Warming Potential, 83 % less land use, 87 % less scarcity-weighted water use, 95 % less freshwater eutrophication, 78 % less marine eutrophication, and 92 % less terrestrial acidification impacts than similar meals with animal source foods, while still offering the same nutritional value as vegan and omnivore meals. The nLCA indices of most novel/future food meals are similar to protein-rich plant-based alternative meals and show fewer environmental impacts in terms of nutrient richness than most animal source meals. Substituting animal source foods with certain novel/future foods may provide for nutritious meals with substantial environmental benefits for sustainably transforming future food systems.

Potential reduction of greenhouse gas emissions from pig production in China on the basis of households' pork consumption

In the past decades, the greenhouse gas (GHG) emissions from pig production in China have been increasing rapidly, which has become a huge challenge in fulfilling China's "carbon neutral" commitment. However, few studies have focused on reducing the GHG emissions from pig production in view of households' pork consumption. This study analyzed the temporal and spatial pattern of the GHG emissions from pig production in China in 2001-2020 through geographical information system, optimized the pig production in China, and estimated thepotentialGHG emissions reduction from pig production in China in 2020 through spatial analysis based on pork surplus or deficit. Results show that the temporal and spatial pattern of the GHG emissions from pig production and its proportion in the total GHG emissions from livestock production in China in 2001-2020 varied differently at the province level and conformed to the "Hu Huanyong Line" mode. The largest and smallest GHG emissions from pig production were 108.93 million tons (MT) in 2014 and 78.10 MT in 2020, respectively. The largest and smallest proportions of GHG emissions from pig production in the total GHG emissions from livestock production were 77.52% in Zhejiang in 2013 and 0.13% in Tibet in 2009, respectively. Moreover, a potential optimization scheme of pig production in China in 2020 was provided and a method of GHG emissions reduction from pig production is proposed. The results indicate that the total potentialGHG emissions reduction from pig production on the basis of households' pork consumption could reach 35.21 MT, accounting for 45.09% of the total GHG emissions from pig production and 10.27% of the total GHG emissions from livestock production in China in 2020. These findings areusefulin the spatial layout planning of pig production, agricultural GHG reduction, and global warming mitigation.

The ensured proliferative capacity of myoblast in serum-reduced conditions with Methyl-β-cyclodextrin

To produce muscle fibers for cultured meat on a large scale, it is important to expand myoblasts in a serum-reduced or serum-free medium to avoid cost, ethical, and environmental issues. Myoblasts such as C2C12 cells differentiate quickly into myotubes and lose their ability to proliferate when the serum-rich medium is replaced with a serum-reduced medium. This study demonstrates that Methyl-β-cyclodextrin (MβCD), a starch-derived agent that depletes cholesterol, can inhibit further differentiation of myoblasts at the MyoD-positive stage by reducing plasma membrane cholesterol on C2C12 cells and primary cultured chick muscle cells. Furthermore, MβCD efficiently blocks cholesterol-dependent apoptotic cell death of myoblasts, which is one of the mechanisms by which it inhibits the differentiation of C2C12 myoblast cells, as dead cells of myoblast are necessary for the fusion of adjacent myoblasts during the differentiation process into myotubes. Importantly, MβCD maintains the proliferative capacity of myoblasts only under differentiation conditions with a serum-reduced medium, suggesting that its mitogenic effect is due to its inhibitory effect on myoblast differentiation into myotube. In conclusion, this study provides significant insights into ensuring the proliferative capacity of myoblasts in a future serum-free condition for cultured meat production.

The microbial food revolution

Our current food system relies on unsustainable practices, which often fail to provide healthy diets to a growing population. Therefore, there is an urgent demand for new sustainable nutrition sources and processes. Microorganisms have gained attention as a new food source solution, due to their low carbon footprint, low reliance on land, water and seasonal variations coupled with a favourable nutritional profile. Furthermore, with the emergence and use of new tools, specifically in synthetic biology, the uses of microorganisms have expanded showing great potential to fulfil many of our dietary needs. In this review, we look at the different applications of microorganisms in food, and examine the history, state-of-the-art and potential to disrupt current foods systems. We cover both the use of microbes to produce whole foods out of their biomass and as cell factories to make highly functional and nutritional ingredients. The technical, economical, and societal limitations are also discussed together with the current and future perspectives.

Engineered Living Materials For Sustainability

Recent advances in synthetic biology and materials science have given rise to a new form of materials, namely engineered living materials (ELMs), which are composed of living matter or cell communities embedded in self-regenerating matrices of their own or artificial scaffolds. Like natural materials such as bone, wood, and skin, ELMs, which possess the functional capabilities of living organisms, can grow, self-organize, and self-repair when needed. They also spontaneously perform programmed biological functions upon sensing external cues. Currently, ELMs show promise for green energy production, bioremediation, disease treatment, and fabricating advanced smart materials. This review first introduces the dynamic features of natural living systems and their potential for developing novel materials. We then summarize the recent research progress on living materials and emerging design strategies from both synthetic biology and materials science perspectives. Finally, we discuss the positive impacts of living materials on promoting sustainability and key future research directions.

Microbial foods for improving human and planetary health

The current food production system is negatively impacting planetary and human health. A transition to a sustainable and fair food system is urgently needed. Microorganisms are likely enablers of this process, as they can produce delicious and healthy microbial foods with low environmental footprints. We review traditional and current approaches to microbial foods, such as fermented foods, microbial biomass, and food ingredients derived from microbial fermentations. We discuss how future advances in science-driven fermentation, synthetic biology, and sustainable feedstocks enable a new generation of microbial foods, potentially impacting the sustainability, resilience, and health effects of our food system.

Differential carbon utilization enables co-existence of recently speciated Campylobacteraceae in the cow rumen epithelial microbiome

The activities of different microbes in the cow rumen have been shown to modulate the host's ability to utilize plant biomass, while the host-rumen interface has received little attention. As datasets collected worldwide have pointed to Campylobacteraceae as particularly abundant members of the rumen epithelial microbiome, we targeted this group in a subset of seven cows with meta- and isolate genome analysis. We show that the dominant Campylobacteraceae lineage has recently speciated into two populations that were structured by genome-wide selective sweeps followed by population-specific gene import and recombination. These processes led to differences in gene expression and enzyme domain composition that correspond to the ability to utilize acetate, the main carbon source for the host, at the cost of inhibition by propionate. This trade-off in competitive ability further manifests itself in differential dynamics of the two populations in vivo. By exploring population-level adaptations that otherwise remain cryptic in culture-independent analyses, our results highlight how recent evolutionary dynamics can shape key functional roles in the rumen microbiome.

Biosynthesis of artificial starch and microbial protein from agricultural residue

Growing populations and climate change pose great challenges to food security. Humankind is confronting a serious question: how will we feed the world in the near future? This study presents an out-of-the-box solution involving the highly efficient biosynthesis of artificial starch and microbial proteins from available and abundant agricultural residue as new feed and food sources. A one-pot biotransformation using an in vitro coenzyme-free synthetic enzymatic pathway and baker's yeast can simultaneously convert dilute sulfuric acid-pretreated corn stover to artificial starch and microbial protein under aerobic conditions. The β-glucosidase-free commercial cellulase mixture plus an ex vivo two-enzyme complex containing cellobiose phosphorylase and potato α-glucan phosphorylase displayed on the surface of Saccharomyces cerevisiae, showed better cellulose hydrolysis rates than a commercial β-glucosidase-rich cellulase mixture. This is because the channeling of the hydrolytic product from the solid cellulosic feedstock to the yeast mitigated the inhibition of the cellulase cocktail. Animal tests have shown that the digestion of artificial amylose results in slow and relatively small changes in blood sugar levels, suggesting that it could be a new health food component that prevents obesity and diabetes. A combination of the utilization of available agricultural residue and the biosynthesis of starch and microbial protein from non-food biomass could address the looming food crisis in the food-energy-water nexus.

Modern Diets and the Health of Our Planet: An Investigation into the Environmental Impacts of Food Choices

Popular modern diets are often seen as a panacea for improving health and promoting weight reduction. While there is a large body of literature reporting the health benefits of popular diets, few studies have described their planetary benefits. Our investigation aims to evaluate the simultaneous impacts of six popular diets within the United States on both human and planetary health. Using carbon footprint databases and representative meal plans, the environmental and health-related impacts of the Standard American, Mediterranean, vegan, paleo, keto, and climatarian diets are compared using the currently available literature. Results indicate that diets that exhibit lower carbon footprints also have positive effects on human health. The diets found to have the lowest environmental impacts were the vegan, climatarian, and Mediterranean diets. These low-carbon-footprint diets can likely be attributed to a reduced reliance on ruminant meat (cattle and sheep) and processed food consumption, while diets with high carbon footprints are more dependent on ruminant meat and saturated fat. Moderate consumption of meats such as chicken, pork, and fish in conjunction with an emphasis on locally grown fruits and vegetables can be maintained without adversely affecting the planetary carbon footprint and with the added benefit of promoting good health. Thus, making simple substitutions within each individual's diet can be advertised as an effective approach to collectively lower the environmental impact in tandem with improving health and longevity.

Unlocking the magic in mycelium: Using synthetic biology to optimize filamentous fungi for biomanufacturing and sustainability

Filamentous fungi drive carbon and nutrient cycling across our global ecosystems, through its interactions with growing and decaying flora and their constituent microbiomes. The remarkable metabolic diversity, secretion ability, and fiber-like mycelial structure that have evolved in filamentous fungi have been increasingly exploited in commercial operations. The industrial potential of mycelial fermentation ranges from the discovery and bioproduction of enzymes and bioactive compounds, the decarbonization of food and material production, to environmental remediation and enhanced agricultural production. Despite its fundamental impact in ecology and biotechnology, molds and mushrooms have not, to-date, significantly intersected with synthetic biology in ways comparable to other industrial cell factories (e.g. Escherichia coli,Saccharomyces cerevisiae, and Komagataella phaffii). In this review, we summarize a suite of synthetic biology and computational tools for the mining, engineering and optimization of filamentous fungi as a bioproduction chassis. A combination of methods across genetic engineering, mutagenesis, experimental evolution, and computational modeling can be used to address strain development bottlenecks in established and emerging industries. These include slow mycelium growth rate, low production yields, non-optimal growth in alternative feedstocks, and difficulties in downstream purification. In the scope of biomanufacturing, we then detail previous efforts in improving key bottlenecks by targeting protein processing and secretion pathways, hyphae morphogenesis, and transcriptional control. Bringing synthetic biology practices into the hidden world of molds and mushrooms will serve to expand the limited panel of host organisms that allow for commercially-feasible and environmentally-sustainable bioproduction of enzymes, chemicals, therapeutics, foods, and materials of the future.

Food for our future: the nutritional science behind the sustainable fungal protein - mycoprotein. A symposium review

Mycoprotein is a well-established and sustainably produced, protein-rich, high-fibre, whole food source derived from the fermentation of fungus. The present publication is based on a symposium held during the Nutrition Society Summer Conference 2022 in Sheffield that explored 'Food for our Future: The Science Behind Sustainable Fungal Proteins'. A growing body of science links mycoprotein consumption with muscle/myofibrillar protein synthesis and improved cardiometabolic (principally lipid) markers. As described at this event, given the accumulating health and sustainability credentials of mycoprotein, there is great scope for fungal-derived mycoprotein to sit more prominently within future, updated food-based dietary guidelines.

Biotechnological Production of Sustainable Microbial Proteins from Agro-Industrial Residues and By-Products

Microbial proteins, i.e., single-cell proteins or microbial biomass, can be cultivated for food and animal feed due to their high protein content and the fact that they represent a rich source of carbohydrates, minerals, fats, vitamins, and amino acids. Another advantage of single-cell proteins is their rapid production due to the growth rate of microorganisms and the possibility of using agro-industrial waste, residues and by-products for production through this renewable technology. Agro-industrial residues and by-products represent materials obtained from various processes in agriculture and agriculture-related industries; taking into account their composition and characteristics, as well as vast amounts, they have an enormous potential to generate sustainable bioproducts, such as microbial proteins. This review aims to summarize contemporary scientific research related to the production of microbial proteins on various agro-industrial residues and by-products, as well as to emphasize the current state of production of single-cell proteins and the importance of their production to ease the food crisis and support sustainable development.

The Potential Role of Iceland in Northern Europe's Protein Self-Sufficiency: Feasibility Study of Large-Scale Production of Spirulina in a Novel Energy-Food System

Europe is dependent on protein-rich crop imports to meet domestic food demand. This has moved the topic of sustainable protein self-sufficiency up the policy agenda. The current study assesses the feasibility of protein self-sufficiency in Iceland, and its capacity to meet Northern Europe's demand, based on industrial-scale cultivation of Spirulina in novel production units. Production units currently operating in Iceland, and laboratory-derived nutritional profile for the Spirulina cultivated, provide the basis for a theoretical protein self-sufficiency model. Integrating installed and potentially installed energy generation data, the model elaborates six production scale-up scenarios. Annual biomass produced is compared with recommended dietary allowance figures for protein and essential amino acids to determine whether Northern Europe's population demands can be met in 2030. Results show that Iceland could be protein self-sufficient under the most conservative scenario, with 20,925 tonnes of Spirulina produced using 15% of currently installed capacity. In a greater allocation of energy capacity used by heavy industry, Iceland could additionally meet the needs of Lithuania, or Latvia, Estonia, Jersey, Isle of Man, Guernsey, and Faroe Islands. Under the most ambitious scenario utilizing planned energy projects, Iceland could support itself plus Denmark, or Finland, or Norway, or Ireland with up to 242,366 tonnes of biomass. On a protein-per-protein basis, each kilogram of Spirulina consumed instead of beef could save 0.315 tonnes CO₂-eq. Under the most ambitious scenario, this yields annual savings of 75.1 million tonnes CO₂-eq or 7.3% of quarterly European greenhouse gas emissions. Finally, practicalities of production scale-up are discussed.

From Food to Gods to Food to Waste

The present global food waste problem threatens food systems sustainability and our planet. The generation of food waste stems from the interacting factors of the need for food production, food access and availability, motivations and ignorance around food purchase and consumption, and market constraints. Food waste has increased over time. This is related to the change in how humans value food through the generations and altered human food consumption and food discard behaviors. There is also a lack of understanding of the impacts of current food production, processing and consumption patterns on food waste creation. This review examines the cultural, religious, social and economic factors influencing attitudes to food and their effects on food waste generation. The lessons from history about how humans strove toward zero waste are covered. We review the important drivers of food waste: waste for profit, food diversion to feed, waste for convenience, labeling, food service waste and household food waste. We discuss strategies for food waste reduction: recovery of food and food ingredients, waste conversion to energy and food, reducing waste from production/processing and reducing consumer food waste, and emphasize the need for all stakeholders to work together to reduce food waste.

Overcoming global inequality is critical for land-based mitigation in line with the Paris Agreement

Transformation pathways for the land sector in line with the Paris Agreement depend on the assumption of globally implemented greenhouse gas (GHG) emission pricing, and in some cases also on inclusive socio-economic development and sustainable land-use practices. In such pathways, the majority of GHG emission reductions in the land system is expected to come from low- and middle-income countries, which currently account for a large share of emissions from agriculture, forestry and other land use (AFOLU). However, in low- and middle-income countries the economic, financial and institutional barriers for such transformative changes are high. Here, we show that if sustainable development in the land sector remained highly unequal and limited to high-income countries only, global AFOLU emissions would remain substantial throughout the 21st century. Our model-based projections highlight that overcoming global inequality is critical for land-based mitigation in line with the Paris Agreement. While also a scenario purely based on either global GHG emission pricing or on inclusive socio-economic development would achieve the stringent emissions reductions required, only the latter ensures major co-benefits for other Sustainable Development Goals, especially in low- and middle-income regions.

The Role of Microorganisms and Carbon-to-Nitrogen Ratios for Microbial Protein Production from Bioethanol

The global protein demand is rapidly increasing at rates that cannot be sustained, with projections showing 78% increased global protein needs by 2050 (361 compared to 202 million ton protein /year in 2017). In the absence of dedicated mitigation strategies, the environmental effects of our current food production system (relying on agriculture) are expected to surpass the planetary boundaries—the safe operating space for humanity—by 2050.

Process Optimization, Amino Acid Composition, and Antioxidant Activities of Protein and Polypeptide Extracted from Waste Beer Yeast

Repurposing of waste beer yeast (WBY) that a main by-product of brewing industry has attracted considerable attention in recent years. In this study, the protein and polypeptide were extracted by ultrasonic-assisted extraction and enzymatic hydrolysis with process optimization, which resulted in a maximum yield of 73.94% and 61.24%, respectively. Both protein and polypeptide of WBY were composed of 17 Amino acids (AA) that included seven essential amino acids (EAA), and typically rich in glutamic acid (Glu) (6.46% and 6.13%) and glycine (Gly) (5.26% and 6.02%). AA score (AAS) revealed that the threonine (Thr) and SAA (methionine + cysteine) were the limiting AA of WBY protein and polypeptide. Furthermore, the antioxidant activities of WBY polypeptide that lower than 10 kDa against hydroxyl radical, DPPH radical, and ABTS radical were 95.10%, 98.37%, and 69.41%, respectively, which was significantly higher than that of WBY protein (25–50 kDa). Therefore, the protein and polypeptide extracted from WBY can be a source of high-quality AA applying in food and feed industry. Due to small molecular weight, abundant AA, and great antioxidant activity, WBY polypeptide can be promisingly used as functional additives in the pharmaceutical and healthcare industry.

Environmental Impacts of Large-Scale Spirulina (Arthrospira platensis) Production in Hellisheidi Geothermal Park Iceland: Life Cycle Assessment

Spirulina algae (Spirulina platensis) cultivated in geothermally powered photobioreactors is here proposed as a potentially resource efficient, zero-carbon, and nutritious alternative to conventional beef meat. Employing a standard life cycle assessment, environmental impacts of large-scale Spirulina production in this facility are calculated. The production facility is sited in Orka náttúrunnar (ON Power) Geothermal Park, Iceland, and benefits from resource streams accessible through Hellisheiði (Hellisheidi) power station, including renewable electricity for illumination and power usage, hot and cold water streams for thermal management, freshwater for cultivation, and CO2 for biofixation. During cultivation, GHG-intensive ammonia-based fertilizers are replaced with macronutrients sourced from natural open mines. LCA results show that production of 1 kg of wet edible biomass in this facility requires 0.0378 m2 non-arable land, 8.36 m3 fresh water and is carbon neutral with - 0.008 CO2-eq GHG emissions (net zero). Compared with conventionally produced meat from beef cattle, Spirulina algae cultured in the ON Power Geothermal Park, referred to in this study as GeoSpirulina, requires less than 1% land and water and emits less than 1% GHGs. Considering food and nutritional security concerns, cultivation in a controlled environment agriculture system assures consistent nutritional profile year-round. Moreover, GeoSpirulina biomass assessed in this study contains all essential amino acids as well as essential vitamins and minerals. While keeping a balanced nutrition, for every kg beef meat replaced with one kg GeoSpirulina, the average consumer can save ~ 100 kg CO2-eq GHGs. It is concluded that environmental impacts of GeoSpirulina production in the Hellisheidi facility are considerably lower than those of conventionally produced ruminants.

Safety evaluation of Neurospora crassa mycoprotein for use as a novel meat alternative and enhancer

Cultivation of filamentous fungi to produce sustainable, nutrient rich meat replacements has recently attracted significant commercial and research interest. Here, we report evidence for the safety and nutritional value of Neurospora crassa mycoprotein, a whole mycelium food ingredient produced by fermentation and minimal downstream processing. N. crassa has a long history of human use in fermented foods and in molecular biology research. A survey of studies that used N. crassa in animal feed revealed no adverse effects to the health of the animals. Furthermore, a review of the literature found no reports of confirmed allergenicity or toxicity in humans involving N. crassa. Genomic toxigenicity analysis and in vitro testing did not identify any toxins in N. crassa mycoprotein. Two independent genomic allergenicity studies did not identify proteins that would be considered a particular risk for allergenic potential. Furthermore, nutritional analysis demonstrated that N. crassa mycoprotein is a good source of complete protein and is rich in fiber, potassium, and iron. Taken together, the presented data and the history of human use without evidence of human or animal harm indicate that foods containing N. crassa can generally be regarded as safe.

Mycelium vs. Fruiting Bodies of Edible Fungi-A Comparison of Metabolites

Edible mushrooms are widely appreciated for their appealing flavours, low caloric values and high content of presumably health-protecting metabolites. Their long history of safe use together with the looming worldwide food crisis have revived the idea of generating meat analogues and protein isolates by the controlled fermentation of mycelia of these edible fungi as a dietary option. The occurrence of proteins, polysaccharides, smaller metabolites, metal ions and toxins in mycelia and fruiting bodies is compared among the three most popular species, Agaricus bisporus (button mushroom), Pleurotus ostreatus (oyster mushroom), Lentinus edodes (shiitake) and some closely related species. Large effects of substrate chemistry, strain, developmental stage and ecological interactions result in a wide variation of the concentrations of some metabolites in both mycelial cells and fruiting bodies. This is obviously a result of the high adaptation abilities required to survive in natural habitats. Fungal bioprocesses are decoupled from agricultural production and can be operated anytime, anywhere, and on any scale according to demand. It is concluded that fungal biomass, if produced under food-grade conditions and on an industrial scale, could provide a safe and nutritious meat substitute and protein isolates with a high biological value for future vegan foods.

Fungal-Derived Mycoprotein and Health across the Lifespan: A Narrative Review

Mycoprotein is a filamentous fungal protein that was first identified in the 1960s. A growing number of publications have investigated inter-relationships between mycoprotein intakes and aspects of human health. A narrative review was undertaken focusing on evidence from randomized controlled trials, clinical trials, intervention, and observational studies. Fifteen key publications were identified and undertaken in early/young adulthood, adulthood (mid-life) or older/advanced age. Main findings showed that fungal mycoprotein could contribute to an array of health benefits across the lifespan including improved lipid profiles, glycaemic markers, dietary fibre intakes, satiety effects and muscle/myofibrillar protein synthesis. Continued research is needed which would be worthwhile at both ends of the lifespan spectrum and specific population sub-groups.