Potential of microbial protein from hydrogen for preventing mass starvation in catastrophic scenarios

Techno-Economic Analysis of Gas Fermentation for the Production of Single Cell Protein

Despite the large carbon footprint of livestock production, animal protein consumption has grown over the past several decades, necessitating new approaches to sustainable animal protein production. In this techno-economic analysis, single cell protein (SCP) produced via gas fermentation of carbon dioxide, oxygen, and hydrogen is studied as an animal feed source to replace fishmeal or soybean meal. Using wind-powered water electrolysis to produce hydrogen and oxygen with carbon dioxide captured from corn ethanol, the minimum selling price (MSP) of SCP is determined to be $2070 per metric ton. An emissions comparison between SCP, fishmeal, and soybean meal shows that SCP has a carbon intensity as low as 0.73 kg CO2-equiv/kg protein, while fishmeal and soybean meal have an average carbon intensity of 2.72 kg CO2-equiv/kg protein and 0.85 kg CO2-equiv/kg protein, respectively. Moreover, SCP production would occupy 0.4% of the land per ton of protein produced compared to soybean meal and would disturb less than 0.1% of the marine ecosystem currently disturbed by fishmeal harvesting practices. These results show promise for the future economic viability of SCP as a protein source in animal feed and indicate significant environmental benefits compared to other animal feed protein sources.

The Fragile State of Industrial Agriculture: Estimating Crop Yield Reductions in a Global Catastrophic Infrastructure Loss Scenario

Modern civilization relies on a complex, globally interconnected industrial agriculture system to produce food. Its unprecedented yields hinge on external inputs like machinery, fertilizers, and pesticides, rendering it vulnerable to disruptions in production and international trade. Such a disruption could be caused by large-scale damage to the electrical grid. Solar storms, nuclear detonations in the upper atmosphere, pandemics, or cyber-attacks, could cause this severe damage to electrical infrastructure. To assess the impact of such a global catastrophic infrastructure loss on major food crops (corn, rice, soybean, wheat), we employ a generalized linear model. The predictions show a crop-specific yield reduction between 15% and 37% in phase 1, the year after the catastrophe, assuming rationed use of fertilizers, pesticides, and fuel stocks. In phase 2, when all stocks are depleted, yields decrease by 35%-48%. Soybean is less affected in phase 1, while all crops experience strong declines in phase 2. Europe, North and South America, and parts of India, China, and Indonesia face major yield reductions, potentially up to 75%, while most African countries are less affected. These findings underscore the necessity for preparation by highlighting the vulnerability of the food system.

Microbial gas fermentation technology for sustainable food protein production

The development of novel, sustainable, and robust food production technologies represents one of the major pillars to address the most significant challenges humanity is going to face on earth in the upcoming decades - climate change, population growth, and resource depletion. The implementation of microfoods, i.e., foods formulated with ingredients from microbial cultivation, into the food supply chain has a huge potential to contribute towards energy-efficient and nutritious food manufacturing and represents a means to sustainably feed a growing world population. This review recapitulates and assesses the current state in the establishment and usage of gas fermenting bacteria as an innovative feedstock for protein production. In particular, we focus on the most promising representatives of this taxon: the hydrogen-oxidizing bacteria (hydrogenotrophs) and the methane-oxidizing bacteria (methanotrophs). These unicellular microorganisms can aerobically metabolize gaseous hydrogen and methane, respectively, to provide the required energy for building up cell material. A protein yield over 70% in the dry matter cell mass can be reached with no need for arable land and organic substrates making it a promising alternative to plant- and animal-based protein sources. We illuminate the holistic approach to incorporate protein extracts obtained from the cultivation of gas fermenting bacteria into microfoods. Herein, the fundamental properties of the bacteria, cultivation methods, downstream processing, and potential food applications are discussed. Moreover, this review covers existing and future challenges as well as sustainability aspects associated with the production of microbial protein through gas fermentation.

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.

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.

Killing two birds with one stone: chemical and biological upcycling of polyethylene terephthalate plastics into food

Most polyethylene terephthalate (PET) plastic waste is landfilled or pollutes the environment. Additionally, global food production must increase to support the growing population. This article explores the feasibility of using microorganisms in an industrial system that upcycles PET into edible microbial protein powder to solve both problems simultaneously. Many microorganisms can utilize plastics as feedstock, and the resultant microbial biomass contains fats, nutrients, and proteins similar to those found in human diets. While microbial degradation of PET is promising, biological PET depolymerization is too slow to resolve the global plastic crisis and projected food shortages. Evidence reviewed here suggests that by coupling chemical depolymerization and biological degradation of PET, and using cooperative microbial communities, microbes can efficiently convert PET waste into food.

Biowaste upcycling into second-generation microbial protein through mixed-culture fermentation

Securing a sustainable protein supply at the global level is among the greatest challenges currently faced by humanity. Alternative protein sources, such as second-generation microbial protein (MP), could give rise to innovative circular bioeconomy practices, synthesizing high-value bioproducts through the recovery and upcycling of resources from overabundant biowastes and residues. Within such a multi-feedstock biorefinery scenario, the wide range of microbial pathways and networks that characterize mixed microbial cultures, offers interesting and not yet fully explored advantages over conventional monoculture-based processes. In this review, we combine a comprehensive analysis of waste recovery platforms for second-generation MP production with a critical evaluation of the research gaps and potentials offered by mixed culture-based MP fermentation processes.

Hydrogen-oxidizing bacteria and their applications in resource recovery and pollutant removal

Hydrogen oxidizing bacteria (HOB), a type of chemoautotroph, are a group of bacteria from different genera that share the ability to oxidize H₂ and fix CO₂ to provide energy and synthesize cellular material. Recently, HOB have received growing attention due to their potential for CO₂ capture and waste recovery. This review provides a comprehensive overview of the biological characteristics of HOB and their application in resource recovery and pollutant removal. Firstly, the enzymes, genes and corresponding regulation systems responsible for the key metabolic processes of HOB are discussed in detail. Then, the enrichment and cultivation methods including the coupled water splitting-biosynthetic system cultivation, mixed cultivation and two-stage cultivation strategies for HOB are summarized, which is the critical prerequisite for their application. On the basis, recent advances of HOB application in the recovery of high-value products and the removal of pollutants are presented. Finally, the key points for future investigation are proposed that more attention should be paid to the main limitations in the large-scale industrial application of HOB, including the mass transfer rate of the gases, the safety of the production processes and products, and the commercial value of the products.

Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection

Atmospheric soot loadings from nuclear weapon detonation would cause disruptions to the Earth’s climate, limiting terrestrial and aquatic food production. Here, we use climate, crop and fishery models to estimate the impacts arising from six scenarios of stratospheric soot injection, predicting the total food calories available in each nation post-war after stored food is consumed. In quantifying impacts away from target areas, we demonstrate that soot injections larger than 5 Tg would lead to mass food shortages, and livestock and aquatic food production would be unable to compensate for reduced crop output, in almost all countries. Adaptation measures such as food waste reduction would have limited impact on increasing available calories. We estimate more than 2 billion people could die from nuclear war between India and Pakistan, and more than 5 billion could die from a war between the United States and Russia—underlining the importance of global cooperation in preventing nuclear war.

Methane Single Cell Protein: Potential to Secure a Global Protein Supply Against Catastrophic Food Shocks

Global catastrophes such as a supervolcanic eruption, asteroid impact, or nuclear winter could cause global agricultural collapse due to reduced sunlight reaching the Earth's surface. The human civilization's food production system is unprepared to respond to such events, but methane single cell protein (SCP) could be a key part of the solution. Current preparedness centers around food stockpiling, an excessively expensive solution given that an abrupt sunlight reduction scenario (ASRS) could hamper conventional agriculture for 5-10 years. Instead, it is more cost-effective to consider resilient food production techniques requiring little to no sunlight. This study analyses the potential of SCP produced from methane (natural gas and biogas) as a resilient food source for global catastrophic food shocks from ASRS. The following are quantified: global production potential of methane SCP, capital costs, material and energy requirements, ramp-up rates, and retail prices. In addition, potential bottlenecks for fast deployment are considered. While providing a more valuable, protein-rich product than its alternatives, the production capacity could be slower to ramp up. Based on 24/7 construction of facilities, 7%-11% of the global protein requirements could be fulfilled at the end of the first year. Despite significant remaining uncertainties, methane SCP shows significant potential to prevent global protein starvation during an ASRS at an affordable price-US$3-5/kg dry.

Nutrition in Abrupt Sunlight Reduction Scenarios: Envisioning Feasible Balanced Diets on Resilient Foods

Abrupt sunlight reduction scenarios (ASRS) following catastrophic events, such as a nuclear war, a large volcanic eruption or an asteroid strike, could prompt global agricultural collapse. There are low-cost foods that could be made available in an ASRS: resilient foods. Nutritionally adequate combinations of these resilient foods are investigated for different stages of a scenario with an effective response, based on existing technology. While macro- and micronutrient requirements were overall met, some-potentially chronic-deficiencies were identified (e.g., vitamins D, E and K). Resilient sources of micronutrients for mitigating these and other potential deficiencies are presented. The results of this analysis suggest that no life-threatening micronutrient deficiencies or excesses would necessarily be present given preparation to deploy resilient foods and an effective response. Careful preparedness and planning-such as stock management and resilient food production ramp-up-is indispensable for an effective response that not only allows for fulfilling people's energy requirements, but also prevents severe malnutrition.

Optimizing Island Refuges against global Catastrophic and Existential Biological Threats: Priorities and Preparations

Human civilization is vulnerable to global catastrophic biological threats and existential threats. Policy to mitigate the impact of major biological threats should consider worst-case scenarios. We aimed to strengthen existing research on island refuges as a mitigating mechanism against such threats by considering five additional factors as well as recent literature on catastrophic risks and resilience. We also analyzed the performance of potential refuge islands during early phases the COVID-19 pandemic. Using a composite indicator (scored from 0-1) based on 14 global macroindices, we present analysis supporting Australia (0.71), New Zealand (0.64), and Iceland (0.58) as the leading candidate island nation refuges to safeguard the survival of humanity and a flourishing technological civilization from the threat of a catastrophic pandemic. Data from the COVID-19 pandemic supports this finding where islands have performed relatively well. We discuss the persisting weaknesses of even the best candidate refuges and the growing literature describing what preparations such a refuge should ensure to enhance resilience. Refuge preparations by Australia and New Zealand, in particular, may additionally provide some immunity against winter-inducing catastrophes such as global nuclear war. Existing disaster resilience frameworks such as the Sendai framework could be worded to mandate preventive measures against global catastrophic and existential threats. The issue of island refuges against certain global catastrophic risks should be raised at relevant international political summits.

Waste-to-nutrition: a review of current and emerging conversion pathways

Residual biomass is acknowledged as a key sustainable feedstock for the transition towards circular and low fossil carbon economies to supply whether energy, chemical, material and food products or services. The latter is receiving increasing attention, in particular in the perspective of decoupling nutrition from arable land demand. In order to provide a comprehensive overview of the technical possibilities to convert residual biomasses into edible ingredients, we reviewed over 950 scientific and industrial records documenting existing and emerging waste-to-nutrition pathways, involving over 150 different feedstocks here grouped under 10 umbrella categories: (i) wood-related residual biomass, (ii) primary crop residues, (iii) manure, (iv) food waste, (v) sludge and wastewater, (vi) green residual biomass, (vii) slaughterhouse by-products, (viii) agrifood co-products, (ix) C₁ gases and (x) others. The review includes a detailed description of these pathways, as well as the processes they involve. As a result, we proposed four generic building blocks to systematize waste-to-nutrition conversion sequence patterns, namely enhancement, cracking, extraction and bioconversion. We further introduce a multidimensional representation of the biomasses suitability as potential as nutritional sources according to (i) their content in anti-nutritional compounds, (ii) their degree of structural complexity and (iii) their concentration of macro- and micronutrients. Finally, we suggest that the different pathways can be grouped into eight large families of approaches: (i) insect biorefinery, (ii) green biorefinery, (iii) lignocellulosic biorefinery, (iv) non-soluble protein recovery, (v) gas-intermediate biorefinery, (vi) liquid substrate alternative, (vii) solid-substrate fermentation and (viii) more-out-of-slaughterhouse by-products. The proposed framework aims to support future research in waste recovery and valorization within food systems, along with stimulating reflections on the improvement of resources' cascading use.