Close

Simple and effective serum-free medium for sustained expansion of bovine satellite cells for cell cultured meat

Andrew J. Stout, Addison B. Mirliani, Eugene C. White, John S.K. Yuen Jr., David L. Kaplan

Preprint posted on May 29, 2021 https://www.biorxiv.org/content/10.1101/2021.05.28.446057v1

On the way to Impossible Burger 2.0: @AJamesStout et al. established a new and easy cell culture medium formulation supporting the production of affordable lab-grown meat

Selected by Kristina Kuhbandner

Background

The earth’s population is growing faster than ever, which comes hand in hand with an increasing demand for food and especially meat. Most likely, conventional meat production will not be able to keep pace with this trend; furthermore, industrial livestock farming has a significant negative impact, among others, on animal welfare and the environment1. In the last few years, plant-based meat alternatives have gained more and more popularity, but many people are not willing yet to reduce their meat consumption, and so far, no product can exactly reproduce the texture and taste of real meat. In an attempt to produce meat in a more sustainable, ethical, and healthy way, labs are trying to grow meat in a dish – also known as cultured or in vitro meat. Although there is a big interest in this emerging technology, many challenges remain such as scalability, food safety, lack of suitable cell culture lines as well as production systems, and cost-effectiveness. A major key in tackling some of the existing limitations is the cell culture medium, which often contains fetal bovine serum (FBS) and accounts for most of the production costs2.  In this preprint, Stout and colleagues present a new serum-free and cost-effective culture medium for the growth of bovine satellite cells (BSCs), the precursors of muscle cells.

 

Main findings

Stout et al. used a previously described medium originally developed for the expansion of human-induced pluripotent stem cells as a starting point. In addition to essential, food-safe nutrients required for cell growth, this B8 medium also contains among others insulin, transferrin, TGFb and FGF-2. First, they compared the ability of serum-free B8 medium and traditional medium supplemented with 20% serum (BSC-GM) to sustain BSC short-term growth. While a 60% serum reduction was well tolerated, B8 alone was not enough to maintain cell growth for more than three days. To address these shortcomings, the authors tested several supplements varying in concentration and composition. Best results were obtained by supplementation of B8 medium with 800 μg/mL animal-free recombinant Albumin. This new formulation termed “Beefy-9” performed similar to serum-containing BSC-GM and was able to maintain cell morphology. In the next step, they established a passaging protocol for the usage of Beefy-9 and verified that passaged cells maintain the capacity to differentiate into muscle cells (Fig. 1).

 

Figure 1 BSC passaging using Beefy-9. (A) Illustration of B8/Beefy-9 passaging protocol (B) Immunofluorescence staining for nuclei (DAPI, blue), actin (Phalloidin, magenta), and Myosin Heavy Chain (MF20, green) in BSCs passaged in Beefy-9 medium according to the protocol. Differentiated cells form multinucleated myotubes positive for the myogenic marker myosin heavy chain. (adapted from Stout et al., Fig. 3, made available under a CC-BY-NC 4.0 International license)

 

Moreover, the use of Beefy-9 during long-term expansion in serum-free conditions was validated. Although BSCs cultured in Beefy-9 medium tended to accumulate lipid droplets, they maintained desired properties of muscle cells. Considering that the cell culture medium is a major cost factor, Stout and colleagues also investigated cost-reduction strategies by reducing the concentration of the expensive growth factor FGF-2. Their results indicate that lowering FGF-2 concentrations has no negative impact on short-term growth. In the same context, it was also shown that by using Beefy-9 and making bulk orders, cell culture medium costs could be reduced by about 70% compared to traditional serum-containing BSC-GM (Fig. 2).

 

 

Figure 2 Analysis of expenses. Costs for BSC-GM, Beefy-9 with high FGF, and Beefy-9 with low FGF were calculated for reagents purchased at a small scale (used in this study) and for reagents ordered in bulk. In both cases, Beefy-9 is more economical than BSC-GM. (taken from Stout et al., Fig. 6, made available under a CC-BY-NC 4.0 International license)

 

Why I like this preprint

In their study, the authors contributed a simple method to make cultured meat production easier and economically more effective and paved the way for further improvements in this field. Further optimization is necessary to reach large-scale production in order to meet the price category of conventional meat. Thus, next to optimizing media, future research efforts could, for example, focus on improving the production of recombinant growth factors, cell line engineering, and the identification of novel protein derivatives or alternatives. Being a vegetarian, I deeply encourage exploring new ways to improve animal welfare. However, there is still a long way to go until products enter local markets, and many issues such as food safety need to be addressed before then. One major step was taken in December 2020, when the Singapore Food Agency made the world’s first commercial approval of cultured meat3. So, it seems possible that in some years we can buy burgers grown in a dish, and I am very excited to follow the future progress in cultured meat research.

 

Questions to the authors

  • Although Beefy-9 is serum-free, the serum is still required in the first step of the passaging process as BSCs are plated in BSC-GM. Do you think it will be possible to completely waive serum in the future?
  • Could Beefy-9 also be used to culture other cell lines relevant for the lab-grown meat industry, such as cells derived from pork or chicken?
  • Can you estimate how many grams of meat could be produced with 10 L of Beefy-9 medium (worth $500)?

 

References

  1. Post, M. J. et al. Scientific, sustainability and regulatory challenges of cultured meat. Nat. Food 1, 403–415 (2020).
  2. Risner, D. et al. Preliminary Techno-Economic Assessment of Animal Cell-Based Meat. Foods 10, 3 (2021).
  3. A. W. and D. W.-B., Singapore becomes first country to approve lab-grown meat. CNN Business https://www.cnn.com/2020/12/02/business/lab-grown-chicken-intl-scli-scn/index.html.

 

Tags: bovine satellite cells, cultured meat, serum-free medium

Posted on: 5th June 2021 , updated on: 7th June 2021

doi: https://doi.org/10.1242/prelights.29418

Read preprint (1 votes)




Have your say

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sign up to customise the site to your preferences and to receive alerts

Register here

Also in the cell biology category:

Fibroblasts

The advances in fibroblast biology preList explores the recent discoveries and preprints of the fibroblast world. Get ready to immerse yourself with this list created for fibroblasts aficionados and lovers, and beyond. Here, my goal is to include preprints of fibroblast biology, heterogeneity, fate, extracellular matrix, behavior, topography, single-cell atlases, spatial transcriptomics, and their matrix!

 



List by Osvaldo Contreras

EMBL Synthetic Morphogenesis: From Gene Circuits to Tissue Architecture (2021)

A list of preprints mentioned at the #EESmorphoG virtual meeting in 2021.

 



List by Alex Eve

FENS 2020

A collection of preprints presented during the virtual meeting of the Federation of European Neuroscience Societies (FENS) in 2020

 



List by Ana Dorrego-Rivas

Planar Cell Polarity – PCP

This preList contains preprints about the latest findings on Planar Cell Polarity (PCP) in various model organisms at the molecular, cellular and tissue levels.

 



List by Ana Dorrego-Rivas

BioMalPar XVI: Biology and Pathology of the Malaria Parasite

[under construction] Preprints presented at the (fully virtual) EMBL BioMalPar XVI, 17-18 May 2020 #emblmalaria

 



List by Dey Lab, Samantha Seah

1

Cell Polarity

Recent research from the field of cell polarity is summarized in this list of preprints. It comprises of studies focusing on various forms of cell polarity ranging from epithelial polarity, planar cell polarity to front-to-rear polarity.

 



List by Yamini Ravichandran

TAGC 2020

Preprints recently presented at the virtual Allied Genetics Conference, April 22-26, 2020. #TAGC20

 



List by Maiko Kitaoka et al.

3D Gastruloids

A curated list of preprints related to Gastruloids (in vitro models of early development obtained by 3D aggregation of embryonic cells). Updated until July 2021.

 



List by Paul Gerald L. Sanchez and Stefano Vianello

ECFG15 – Fungal biology

Preprints presented at 15th European Conference on Fungal Genetics 17-20 February 2020 Rome

 



List by Hiral Shah

ASCB EMBO Annual Meeting 2019

A collection of preprints presented at the 2019 ASCB EMBO Meeting in Washington, DC (December 7-11)

 



List by Madhuja Samaddar et al.

EMBL Seeing is Believing – Imaging the Molecular Processes of Life

Preprints discussed at the 2019 edition of Seeing is Believing, at EMBL Heidelberg from the 9th-12th October 2019

 



List by Dey Lab

Autophagy

Preprints on autophagy and lysosomal degradation and its role in neurodegeneration and disease. Includes molecular mechanisms, upstream signalling and regulation as well as studies on pharmaceutical interventions to upregulate the process.

 



List by Sandra Malmgren Hill

Lung Disease and Regeneration

This preprint list compiles highlights from the field of lung biology.

 



List by Rob Hynds

Cellular metabolism

A curated list of preprints related to cellular metabolism at Biorxiv by Pablo Ranea Robles from the Prelights community. Special interest on lipid metabolism, peroxisomes and mitochondria.

 



List by Pablo Ranea Robles

BSCB/BSDB Annual Meeting 2019

Preprints presented at the BSCB/BSDB Annual Meeting 2019

 



List by Dey Lab

MitoList

This list of preprints is focused on work expanding our knowledge on mitochondria in any organism, tissue or cell type, from the normal biology to the pathology.

 



List by Sandra Franco Iborra

Biophysical Society Annual Meeting 2019

Few of the preprints that were discussed in the recent BPS annual meeting at Baltimore, USA

 



List by Joseph Jose Thottacherry

ASCB/EMBO Annual Meeting 2018

This list relates to preprints that were discussed at the recent ASCB conference.

 



List by Dey Lab, Amanda Haage
Close