Cellular Agriculture: An Outlook on Smart and Resilient Food Agriculture Manufacturing

Over the centuries, the application of grassland and cutting of livestock are the primary foundations for the production of food agriculture manufacturing. Growing human population, accelerated human activities globally, staggering food inequity, changing climate, precise nutrition for extended life expectancy, and more demand for protein food call for a new outlook to smartness in food agriculture manufacturing for delivering nutritious food. Cellular agriculture, 3D printing of food, vertical urban farming, and digital agriculture alongside traditional means are envisioned to transform food agriculture and manufacturing systems for acceptability, availability, accessibility, affordability, and resiliency for meeting demands of food in this century for communities across the US and the world. This technical note illustrates the thought leadership for cellular agriculture as a part of the new food agriculture manufacturing revolution. 1. Drivers for food agriculture manufacturing revolution It is estimated that the world population will reach 9.5 billion by 2050 [1]. The food supply for this growing population will be constrained due to limited resources, land, water, and the impacts of climate change. The issue is how to sustainably feed a growing population with minimal impact on the environment and resource consumption while ensuring dietary wellbeing. Approaches such as digital agriculture (use of Industry 4.0 principles in farming), vertical urban farming (for local and resourceconstrained fresh produce) alongside alternative protein manufacturing are being explored to increase food production and meet consumer demands. For the majority of this world population, animal protein is a critical food nutrient source for a balanced diet and it is predicted that the global demand for this protein will double by 2050 [2–4]. In the US, it was reported that about 78% of consumers rely on meat as a source of protein [5]. USDA projects both meat production and demand to steadily increase over the coming years [6]. Over the years, cutting animals for meat has evolved from huntergatherers -to local butchers -to large-scale industrial slaughterhouses. Even though the efficiency and outputs of meat production have increased, the modus operandi has stayed the same cutting animals raised through farms, ranches, and others. Over the last few decades, it has been recognized that this top-down manufacturing approach of cutting animals is resource-intensive in terms of land, water, This manuscript is submitted to ASTM ‘Smart and Sustainable Manufacturing’ journal energy, and time. Additionally, the macro supply chains of meat processing, packaging, and transportation remain vulnerable to disruptions, a fact recently evidenced during the COVID-19 pandemic, worsening food insecurity and challenging the resilience of communities [7]. The above factors, in addition to, distribution inequity, growing concerns over the spread of zoonotic diseases [8], and reducing animal cruelty call for new disruptive thinking for the development of complementary sustainable and humane food production approaches (schematically represented in Figure 1) [9–11] as a part of the upcoming food agriculture manufacturing revolution delivered by the convergence of many disciplines. Figure 1: Potential benefits of alternative cell-based protein meat manufacturing Complementary to today’s livestock and poultry farming, two protein-rich food production approaches [12] to address these issues are plant-based meat and cell-based meat (also called cultivated meat or invitro meat). Plant-based meat alternatives have attracted significant attention over the last few years through the introduction of meat substitutes by Beyond Meat®, Impossible® Foods, and others into the market. However, it is noted that these plant-based protein sources, when compared to beef, have lower levels of some essential amino acids like lysine and methionine, vitamin B12, minerals, and some secondary nutrients [13]. Additionally, these products primarily [14] appeal to a limited population with vegetarian and vegan (a minority of the population) dietary interest. Their nutritional benefits as highly processed foods are still being debated and their advantage over eating established plant-based foods (vegetarianism as observed in older cultures like in India and other parts of the world) remains questionable. On the other hand, manufacturing of cell-based meat (CBM), which has an identical physicochemical composition to conventional meat products has the potential to have a significant impact on American (2018 Gallup poll, only 5% of U.S. adults consider themselves to be vegetarian [15]) This manuscript is submitted to ASTM ‘Smart and Sustainable Manufacturing’ journal and global nutrition, meat production, and distribution systems as a part of future food agriculture manufacturing. Since this field is still in infancy, this is an opportune time to map and incorporate CBM manufacturing into flexible, customizable supply chains [16], as a part of sustainable and smart manufacturing. This paper presents open challenges and opportunities for cellular agriculture as a part of sustainable food agriculture manufacturing. 2. Cellular Agriculture (Cell-Ag, CA): State-of-the-art, opportunities, and challenges 2.1 Overview of cellular agriculture process steps Since the unveiling of the $325,000 in-vitro burger by Dr. Mark Post in 2013 [17], the cellular agriculture industry has progressed in reducing the costs to a certain extent associated with cell-based meat (CBM) with cultured chicken nuggets now being served in Singapore [18]. This section will introduce cellular agriculture to the readers and give an overview of the current challenges and research innovation opportunities in CBM production. For this manuscript, cellular agriculture is defined as the manufacturing of animalor bio-inspired protein food derived from cell-cultures producing cell-based foods. Typically, CBM production involves extraction and isolation of stem cells from the animal, subsequent cell growth, proliferation, and differentiation in increasing sizes of bioreactors containing cell culture medium followed by meat harvesting as summarized in Figure 2 [19]. The individual processing steps shown in Figure 2 each have their own unique scientific and technological barriers for large-scale production and are discussed in the next subsection. 2.2 At-scale manufacturing challenges for cellular agriculture Current steps as outlined above and state-of-the-art approaches in the industry are derived from tissue engineering and biomedical manufacturing methods. But for CBM, tissue production needs to be Figure 2: Process schematic for manufacturing cell-based meat [19] This manuscript is submitted to ASTM ‘Smart and Sustainable Manufacturing’ journal inexpensive and manufactured at a much larger scale compared to the aforementioned approaches for its affordability as a consumer food product. For comparison, the cost of organs cultured with biomedical tissue engineering methods justifies the expensive cell lines and culture media but for CBM production, the cost needs to be comparable to conventional meat [20], and therefore, needs to be orders of magnitude lower. On the other hand, even large-scale tissue culturing methods for therapeutic purposes result in the final culture comprising of ~10-10 cells [21] contained in ~5L bioreactor [22] for clinical scale but for CBM, the final culture needs to comprise of ~10 cells (with ~10 cells/kg) housed in a ~10000-liter bioreactor [23]. In addition to that, the resulting CBM should be similar or superior to conventional meat in sensorial and nutritional aspects [24]. Therefore, the manufacturing of CBM needs to overcome numerous serious scientific and manufacturing challenges. These challenges can be broadly classified [25] into four categories (see Figure 3): (a) cell lines, (b) cell culturing, (c) bioreactor design, and (d) scaffold design. Figure 3: Challenges and opportunities for cellular agriculture meat manufacturing a. Cell line: The selection of appropriate cell lines from an appropriate species of interest is important for being able to manufacture the high number of cells in the final culture as well as controlling their differentiation into fat, muscle, and connective tissue at desired locations. On the later issue, choice of starter cell(s) will dictate the downstream optimization of cell-culture media, nutrient delivery, scaffold design, and bioreactor design to achieve location-specific expression of desired tissues. This manuscript is submitted to ASTM ‘Smart and Sustainable Manufacturing’ journal b. Culture Media: The growth and differentiation are also controlled by cell culture media used at various stages of manufacturing. The medium needs to be optimized with required nutrients and growth factors at each stage for the cell line used and its cost needs to be lowered with manufacturing processes for its components being suitably modified following economies of scale [26]. For this, and for reproducibility, the culture media also needs to be serum-free i.e., it should not contain Fetal Bovine Serum, Horse Serum, or any other living animal-derived component [27]. c. Bioreactors: For bioreactors, two key challenges for research and innovation are addressing nutrient transport and mixing limitations and sterilization. Addressing the first challenge involves the design of bioreactors such that no significant gradients in nutrient and oxygen concentrations exist throughout the volume at each stage and this homogeneity needs to be achieved without increasing the shear rates for agitation which may cause cell death. For the second challenge, in addition to accommodating the sterilization constraints similar to industrial fermenters for bioreactors and supporting equipment design, it will be important to limit/eliminate the use of antibiotics (as is common in tissue culturing) in t