A review: Cellular Agriculture Cultivated Meat-Making with A Focus on the Bioreactor

The traditional methods of bringing meat from farm-to-fork have many issues,” Harvestable land per capita is decreasing, and climatic conditions are exponentially challenging nutritious food equity. The breakthrough idea of cellular agriculture and alternative protein food is to leverage our existing expertise at the convergence of multiple disciplines to create new opportunities for much higher efficiency, much lower natural resource impact, and new earning and job opportunities for urban and rural farmers. Meat has long served human cultures as a dense source of essential nutrients and will continue to do so in the future. Cellular agriculture focuses on the production of agricultural products from cell cultures using a combination of biotechnology, tissue engineering, molecular biology, and synthetic biology to create and design new methods of producing proteins, fats, and tissues that would otherwise come from traditional agriculture.Cultured meat (also referred to as cultivated meat or cell-based meat)—CM—is fabricated through the process of cellular agriculture (CA), which entails application of bioengineering, i.e., tissue engineering (TE) principles to the production of food. The main TE principles include usage of cells, grown in a controlled environment provided by bioreactors and cultivation media supplemented with growth factors and other needed nutrients and signaling molecules, and seeded onto the immobilization elements— micro carriers and scaffolds that provide the adhesion surfaces necessary for anchor-dependent cells and offer ۳D organization for multiple cell types.Tissue engineering is employed to make cell-based or cultivated meat, seafood and milk. To produce cell based meat and seafood, natural or genetically modified stem cells are taken from a live animal and grown in nutrient-rich conditions in a bioreactor, utilizing nature’s own growth and repair mechanisms. The cells differentiate into types – either muscle or fat cells – then are grown on a scaffold or further processed as ground meat. A variety of methods can be selected for scaling cultivated meat production past bench into pilot and commercial scales. Broadly speaking, these methods can be broken up categorically into batch, fed-batch, continuous, and perfusion. In batch culture, a vessel is filled with a fixed volume of media and cells are grown to their maximum density before being harvested or transferred to a larger vessel. In fed-batch culture, cells grown in a vessel are fed fresh medium from an in-line, independent feed vessel at variable rates in order to maximize properties such as exponential cell growth or cell densities. In continuous culture, cells are grown in a vessel and fresh medium is added via an in-line feed vessel at an optimized flow rate, while product, cells, or medium are simultaneously collected in an independent collection vessel at the same or alternative rate. Lastly, perfusion culture is a subset of continuous culture wherein the cells are retained via a substrate or collection method, permitting medium recycling integration and high cell densities in a smaller space. Each method has potential benefits and caveats, and it is possible that multiple methods may be used throughout a cultivated meat bioprocess. There are many different bioreactor designs to choose from that can be separated based on how the medium is mixed and whether the cells are grown in suspension or adhered to a solid surface. For animal cell culture, the most commonly used bioreactor is a continuous stirred tank reactor, as it offers greater long-term sterility and reduced bubbling versus air-lift reactors at scale. In general, continuous stirred tank reactors permit growth of cells in suspension via mechanical stirring while maintaining high mass transfer of oxygen. Similar suspension growth results can be obtained with rocking platform bioreactors and vertical wheel bioreactors, albeit at smaller maximum scales. Suspension growth can also occur with attachment-dependent cells through the use of micro carriers. In this mini-review we focus on the design of the expansion bioreactor, and put it in context of the entire bioprocess, as a full-scale cultured meat bioprocess is still hypothetical, we include a review of the key factors and fundamental cell biology parameters required as input data for the design of a process with a product that is not only viable but price competitive.

Keywords:

cultured meat , cultivated meat , cell-based meat , cellular agriculture , bioengineering , tissue engineering , bioreactor , sustainably meet.