To fix carbon, food, energy: fix RuBisCO (the mother of all biofuels challenges)
Model of the RuBisCO enzyme
If Rubisco sounds like a mash-up of “renewable energy” and “Nabisco”, the international food marketer, it is a coincidence but a happy one. For nothing is more key to the future of both than the RuBisCO enzyme.
It was the biochemist Dr. Ganesh Kishore, now the CEO of the Malaysian Life Sciences Capital Fund and formerly Chief Biotechnology Officer of Dupont, who raised the issue at a recent Burrill & Company Limited Partners meeting, when he said that biofuels research, while impressive and laudable, is overly focused on midstream processing technologies and not on the key factor: the appallingly low rate at which plants convert sunlight to energy.
The problem of photosynthetic efficiency
For example, corn checks in with a 1-2 percent efficiency rate. Raise photosynthetic efficiencies to 10-12 percent, said Kishore: that’s the opportunity. It’s of the most interesting points raised this year in biofuels circles, for with such a fix, so many of the concerns about biofuels – cost parity, food vs fuel, the cost of transporting biomass – begin to melt away.
Which brings us to the problem child, Rubisco, or by its full name ribulose-1,5-bisphosphate carboxylase oxygenase. Though obscure to the average citizen, it is not at all uncommon; in fact, it is the most abundant protein on earth.
It’s role: it is the enzyme that catalyzes the first step in the fixation of atmospheric carbon (for most plants, and also for cyanobacteria) – in short, it is a gateway to plant growth and carbon sequestration.
Slow, dim-witted RuBisCO
Though abundant, it is a slow, dim-witted enzyme if ever there was one. So slow that it fixes just three carbon molecules per second, and so dim-witted that it has trouble distinguishing between oxygen and CO2. Under many conditions, it will fix oxygen instead of CO2, in a process called plant respiration which causes carbon loss and robs the plant of growth opportunity.
Speed up, and smarten up Rubisco, and like a freeway with a slow tollway removed, bioproductivity can reach levels that support the food we need and the energy to convert crops into both food and fuel.
It is a tempting subject which should have long ago attracted an X Prize, or some other glittering strategic research funding. Instead, the big bucks are funding processing technologies — which only exacerbate the dilemma of food vs fuel by making fuel cheaper and cheaper to produce from overly-expensive feedstocks, and further tempts the land use change by which the industry has been bedeviled.
Compared to the millions lavished on other areas of energy research, RuBisCO research is a underfunded corner. For sure, it is the subject of devoted research by a number of academics and the USDA (among others), but hardly receives the central focus commensurate with its position, squatting at the junction of so many national priorities. It has a highly talented cadre of researchers who have manned the battlements for a long time; they deserve reinforcement.
Scaling up biofuels — in the wake of the BP oil spill
In the wake of the BP oil spill in the Gulf of Mexico, many are groping for immediate solutions, and the Renewable Fuels Association among others have pointed strongly to scale-up biofuels providing the best near-term alternative to more drilling, and more dependence on fossil-based oil.
Yet biofuels has critics, and though many are ridiculous, many are worth lending an ear. Why? The problem underlying biofuels – advanced or otherwise – upon which critics train their daggers, is alarmingly simple: it is the absence of sustainable, affordable biofuels feedstocks at scale.
In the global transition from fossil-based fuels — 1.2 trillion gallons of conventional fuels up for grabs, which would require in the neighborhood of 10-20 billion tons of biomass per year in additional, recoverable biomass resources. Let’s put that in context – the entire US corn harvest weights in at around 370 million tons. The disgareement between foodies, environmentalists, cattle and dairy interests, and energy security advocates are all driven by low photosynthetic efficiencies.
It is a debate driver — in some corners a hate driver — and surely in the developing world it is a barrier to the economic progress that would produce stability and peace. We disagree because of different priorities, and it is important to debate over the just division of a pie. But in a world where hunger exists, and fossil fuels are running out, it is more important to make more pie, if it can sustainably be made.
Limits of sustainable, affordable biomass
US biofuels forecasts tend to think in terms of 1 billion tons of sustainable biomass — an estimate widely considered an optimistic scenario. Though non-conventional platforms such as algae or cyanobacteria promise to extend that, the 2008 “food vs fuel” cacophony is only the opening salvo in a long war over the who, what, and why of control of biomass resources. Land grabs, policy grabs, or guilt-tripping the nation with false choices such as “food vs. fuel” are one set of approaches. Lifting the yield performance of a target crop is another. Producing more biomass across the board with smarter, faster RuBisCo – that’s better.
Food crisis, or income distribution crisis
There is more at stake than biofuels. For the world produces more food per capita today than in 1960, and the world hunger crisis that NGOs and the UN talk about is not a crisis of food distribution, but income distribution. 50 percent of the world’s population lives in rural areas, and there is no solving the world’s income distribution problems without solving the problem of rural income. Biofuels provide the best-known mechanism for improving rural income in the long-term.
What else is the product of improved rural incomes? Well, for one, smaller families — for it is a well-established demographic fact that more affluent families have fewer children. With fewer mouths to feed, less pressure of population growth, and pressure on scarce water and food resources. Not to mention the reduced pressure on carbon emissions from smaller populations.
The challenge of rural productivity
It’s all tied up in rural productivity, and ultimately in biofuels — but more presently and urgently in feedstock productivity, which needs more attention, and now. Now at the margins of improving yields, and drought and pest resistance, but in the hard transformative work of focusing on photosynthetic efficiency.
Only in that scenario is there the real hope for what Syngest CEO Jack Oswald called “energy abundance“. Where do the answers lie in terms of re-educating this pervasive, utterly ancient, and incredibly slothlike enzyme?
Assuredly in genetic engineering, and perhaps in that other forgotten child of biomass research, the red algaes – known primarily to the public as the source of sushi-wrapping seaweed.
Promising work has been done in exploring the genetic structure of certain red algaes for traits that might address the deficiencies in Rubisco. More is needed.
Moore’s Law and genetic research
But a different kind of educational effort is also required. For we are in a Moore’s Law environment in gene sequencing technology, where the speed and cost of sequencing is falling by a factor of 2 every year. It cost $3 billion and took years to sequence the human genome, in a project which was completed in 2003. Today, it takes 60-90 days and costs $48,000. By 2012 or so, the cost is expected to drop as low as $1,000.
But take it out to 2022, the last year of the Renewable Fuel Standard – why that’s 2 to the 12th power – by Moore’s Law, we might expect a genome to be sequenced in a half an hour for under $12. That’s 6 billion base pairs per hour. That’s a mountain of data.
The time to train the analysts and develop the tools is now. 6 billion base pairs will not analyze themselves.
That’s the secret of unlocking Rubisco’s potential. That’s the task worthy of a national – or international research goal. Much talk has been expended about a Manhattan Project, or Apollo Project – for energy security, for food security, for climate security.
Such a herculean effort might best target Rubisco — and the answer lies within for all three.
Notes and further reading
Notes on research in the field: There is a lot of RuBisCO research by many keen minds – more is needed. The USDA ARS collects information on research efforts, noting that approximately 200 papers on the topic are published each year. Here’s a link to their work. Here’s a good history also, from the University of Illinois.
Here’s a good primer on RuBisCO, from the RCSB Protein Data Bank.
An example, a leading researchers on Rubisco engineering is the Matsumura lab at Emory University.
Back in 2006, progress was reported on a RuBisCO mutant gene that “exhibited 5- fold improvement in specific activity relative to the wild-type enzyme. According to the scientists, such large changes in RuBisCO efficiency could potentially lead to a faster plant growth, quicker sequestration of the CO2 from the air and more efficient plant removal of greenhouse gasses from the atmosphere.”
Who can do something: Besides ongoing work at the USDA, the National Science Foundation and the DOE Office of Science have opportunities to increase funding in this area. Earmarks from Congress can go a long way towards galvanizing basic research, even though, as typically implemented, “The best that can be said is that they are a nuisance,” according to former DOE deputy assistant secretary David Conover. Congress allocated $445 million for earmark projects in 2010, which a DOE-friendly article in the Wall Street Journal described as “sapping the Energy Chief’s priorities.”
View from the other side: David Tyler, in his blog hosted on the Access Research Network, writes: Over the past decade, the pendulum has swung away from the idea that Rubisco is unintelligent design. Its achievements are remarkable.
Nature Magazine’s take: John Ellis, writing in the January 14th 2010 Nature this year, opines: “The key enzyme in photosynthesis, Rubisco, is a relic of a bygone age. The ability to assemble Rubisco in the test tube offers the prospect of genetically manipulating the enzyme to make it fit for the modern world. Rubisco is the most important enyzme on the planet — virtually all the organic carbon in the biosphere derives ultimately from the carbon dioxide that this enzyme fixes from the atmosphere. But Rubisco is also one of the most inefficient enzymes on the planet.”
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