Synthetic biology has helped incorporate the smells, taste and texture of the planet-destroying beef burger into a vegan burger
By S Ramadorai, Raman Srinivasan & S Shivaramakrishna
In a previous article, we saw Pat Brown’s vision of a novel burger, better for the consumer, the planet, and the cow (FE, June 16; ‘The coming Industrial Revolution’; https://bit.ly/3iQjjLW). Not surprisingly, he held his vegan burger to high standards. One, it would be nutritionally equivalent to, if not healthier, than a beef burger. Two, the better burger would reduce the planet-destroying impact of beef burgers by 90%. Three, the innovative new burger would be indistinguishable from a beef burger in terms of colour, aroma, taste, texture and mouthfeel. Furthermore, it would cook in the same manner as a meat patty, allowing the consumer to experience the same cravings, aromas, colours and textures. And finally, the better burger would be more affordable as well.
Unearthing blood: A multidisciplinary effort was required. Sue Klapholz, a biochemist and spouse of Brown, began to lead the research and development to ensure nutritional equivalence of the innovative new vegan burger. In order to create a facsimile of the beef burger patty, leguminous plants were uprooted to extract leghemoglobin. Often called plant blood, leghemoglobin rendered the vegan burger patties pinker, bloodier and meatier. In order to find a sustainable and scalable solution, Brown turned to synthetic biology.
Like many projects in synthetic biology, a five-step process followed. As an initial step, scientists in his team sequenced or ‘read’ the genomes of dozens of leguminous plants in the lab. Soon, biologists identified the specific genes responsible for the production of leghemoglobin in various legumes. Then, in the third step, the native genetic code for heme production was inserted (much like a writer inserting a quotation from another text) in widely used yeast called Pichia pastoris. Step four was a fermentation process not unlike brewing beer. The yeast with the heme-producing code in quotes was fed with glucose and grown under precisely controlled conditions. Lo and behold! Pichia pastoris produced a frothy red plant blood in one of the lab-scale fermenters. The fifth step in the process was to decant and purify this leghemoglobin for further use.
The team of synthetic biologists at Brown’s start-up produced leghemoglobin using genetic code from multiple legume species. They were systematically incorporated into various early versions of the burger. Finally, they decided to scale up the production of Soy leghemoglobin in industrial scale fermenters. The heme-alayas in Oakland, California, produce a frothy blood red brew, rich in heme.
Addressing anaemia: Heme-alayas can help address a pernicious problem in our society. Our data shows that 50% of young Indian women are anaemic. Haemoglobin levels average at 7 gm/decilitre. Commonly associated symptoms include constant fatigue and an inability to concentrate. Iron-deficiency anaemia is a problem with negative impact across multiple generations. When young anaemic women get pregnant, it results in complications and the children they give birth to also tend to be of low-birth weight, leading to lifelong health issues as well in the subsequent generations. Plant origin heme-enriched water with added macro and micro nutrients can help address this unsolved problem. The transmission chain of ill-health across multiple generations and centuries can be broken in less than a decade.
Dollars and scents
Neuroscience of the better burger: In the quest for the perfect burger, leghemoglobin solved key design challenges. But the quest for replicating the craving for red meat remained. Brown set himself a high bar. His vegan burger needed to be functionally and culturally equivalent to cow meat in all aspects. It had to sizzle and ooze blood when grilled. The very sight and smells of his burger being cooked had to, of course, trigger all the pleasant and deep memories associated with meat.
So, analytical chemists hooked up a Gas Chromatograph-Mass Spectrometer up to a grill, and lab members identified key aroma molecules, amongst the thousands of volatiles released, that contributed to the smell of beef being cooked. But that was not quite enough. One of Brown’s siblings, Richard, an accomplished neuroscientist, joined the team to get the neurochemistry of consuming a burger absolutely right.
Smell, one of our most ancient senses and until relatively recently a scientific mystery as well, can trigger powerful memories of love and pleasure. It was really critical to identify the right combination of volatiles to recreate the experience of cooking and eating meat. Based on several experiments, scientists mapped out the neuro and biochemistry of aroma-flavour design space for various meats.
The final step in reverse engineering a burger patty was to figure out a way to encapsulate fat components (coconut oil, for example) in pockets of potato protein, interspersed in a matrix of soy protein isolate. This revolutionary new vegan burger, when cooked sizzled, oozed out juicy fat, smelled and charred just like cow meat. And when volunteers bit into the burger, the mouthfeel of the vegan patties was remarkably convincing. Finally, to paraphrase Rudyard Kipling: “Yeast is yeast, and West is West, and the twain shall meat.”
Influential technology investors like Bill Gates in the West view synthetic biology as a solution to multiple problems of climate change, public health burden and factory farming. As a witness to the rapid progress in synthetic biology, Gates became an early investor in several other start-ups as well, in the ‘synthetic meat’ space.
‘The cow is an obsolete technology.’
—Patrick O Brown
Ramadorai is former vice-chairman, TCS; Srinivasan is head, TCS Ignite;
and Shivaramakrishna is researcher, TCS