Abstract
Current projections estimate that in 2050 about 10 billion people will inhabit the earth and food production will need to increase by more than 60%. Food security will therefore represent a matter of global concern not easily tackled with current agriculture practices and curbed by the increasing scarcity of natural resources and climate change. Disrupting technologies are urgently needed to improve the efficiency of the food production system and to reduce the negative externalities of agriculture (soil erosion, desertification, air pollution, water and soil contamination, biodiversity loss, etc.). Among the most innovative technologies, the production of microbial protein (MP) in controlled and intensive systems called “bioreactors” is receiving increasing attention from research and industry. MP has low arable land requirements, does not directly compete with crop-based food commodities, and uses fertilizers with an almost 100% efficiency. This review considers the potential and limitations of four MP sources currently tested at pilot level or sold as food or feed ingredients: hydrogen oxidizing bacteria (HOB), methanotrophs, fungi, and microalgae (cyanobacteria). The environmental impacts (energy, land, water use, and GHG emissions) of these MP sources are compared with those of plant, animal, insect, and cultured meat-based proteins. Prices are reported to address whether MP may compete with traditional protein sources. Microalgae cultivation under artificial light is discussed as a strategy to ensure independence from weather conditions, continuous operation over the year, as well as high-quality biomass. The main challenges to the spreading of MP use are discussed.
Highlights
As concerns future food demand and supply, most analysts agree on the necessity to increase food production by more than 60% in the three decades to satisfy the needs of the world’s growing population and income-dependent global dietary shift [1,2]
5000 tonnes year−1 and spirulina with about 15,000 tonnes year−1 comprise over 80% of the world microalgal biomass production, which, without considering phytoplankton produced in hatcheries, totals about 25,000 tonnes annually [61]
At a first glance, that there is no advantage in using artificial light, but we need to consider all the benefits of not relying on sun as the energy source, among which are the independence of weather conditions and continuous operation over the year, constant production and reliability of supply, high and constant biomass quality, lower costs for thermoregulation, the possibility to adjust biomass composition and enhance the content of target products, the possibility to satisfy algal species requirements in terms of light quality and intensity, and expected better performances as PV and Light emitting diodes (LED) efficiencies improve and costs decrease
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Reducing the consumption of animal products will be a key determinant to avoid further biodiversity losses, limit adverse impacts of agriculture on soil, water and atmosphere, and mitigate climate change as the livestock sector appropriates 80% of agricultural land (4.0 out of 5.1 billion hectares) and accounts for 29–43% of the total agricultural water footprint, 46–76% of agricultural GHG emissions, and 34–58%. One of the major environmental benefits associated with food production from microbial biomass lies in the efficient use of nitrogen, phosphorus, and other nutrients. HOB are mostly chemo-litho-autotrophs, i.e., they use inorganic electron (H2 ) and carbon (CO2 ) sources to grow and produce biomass, offering large CO2 -emitting industries a tool to reduce their carbon footprint and produce, at the same time, feed, food, or green chemicals [17]. By [19]. c QuornTM products refers to mince and pieces with a content of mycoprotein of about 95%. d QuornTM retail price [41]
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