Mega-factories should make way
The burning stacks that typify many industrial sites are seen as a wasted opportunity by engineers.
A team of Rice University engineers have outlined new ideas for excess methane that they believe represents an opportunity for biomanufacturing that should not be missed.
Given the steady advance of biomanufacturing - using of wild or genetically-modified bacteria to turn carbon-rich methane and other substances into valuable chemicals - it should be possible to produce chemicals on a smaller, more environmentally friendly scale.
But it would require a shift from current thinking, which says economic viability can come only from the economies of unit scale afforded by large facilities.
Rice University professor Ramon Gonzalez - who specialises in genetically engineering bacteria for biotechnology – says advances in metabolic engineering, genomics and industrial process design have pushed industrial biomanufacturing closer than ever to widespread adoption.
However, he argues it could and should go much further.
“Biotech in general has four branches of applications: Medical, agricultural, environmental and industrial, the one in which we primarily work,” said Gonzalez, a professor of chemical and biomolecular engineering.
“The industrial side aims at generating molecules that are produced these days from many feedstocks, including oil and natural gas.
“What has not been explored much in this space is what biology brings to the table, regardless of whether you use starting materials that are renewable or not.”
Renewable feedstocks include corn and lignocellulosic biomass used to produce ethanol and other molecules.
Nonrenewables include oil and gas used to produce thousands of chemicals required by industry, typically at immense facilities that offer economies of scale.
Gonzalez says small-scale biomanufacturing is usually associated with renewable sources, but he and his team do not see that as the only use
“You don't need to go big,” he said.
“This is an area that almost nobody explores. Actually, companies are doing the contrary, they are saying; ‘Let's go big with biology’ and forcing it to do things that are not a natural fit for biomanufacturing. That's not necessarily what biology is good at.”
He said studies have shown that waste methane burned off in 2014 alone could have been transformed via biomanufacturing into seven important organic chemicals - methanol, ethylene, propylene, butadiene, xylene, benzene and toluene - in amounts sufficient to meet 100 per cent of industry's needs that year.
“Between flared methane, waste-treatment facilities situated near population centres and agricultural facilities around the country, we have a lot of feedstock,” Gonzalez said.
“You might say these are little things, but when you add them up - and we have run that number - we find we can produce most of the chemicals that we need today.”
He argues that these feedstocks are not easily accessible to megafacilities that require large quantities of mostly fossil-based raw materials, but that biomanufacturing facilities operate at much smaller scales and require about the amount of feedstocks that distributed (and often wasted) methane-generating sites create.
A distribution of small factories puts them closer not only to feedstocks but also to point of need, which Gonzalez says would also facilitate faster innovation and a more rapid response to the needs of the market.
As an example, he points to the network of small, strategically placed bioconversion facilities have increased the USA’s ethanol output tenfold over the past two decades.
The engineers say now is the time, as the science of programming bacteria like fast-growing E.coli to make chemicals using genome-editing techniques like CRISPR/Cas-9 is rapidly catching up to the demand.
“Do you need to produce millions of tons of chemicals?” Gonzalez asked.
“How are you going to do that if you have a small plant and still make an impact? Well, if you have hundreds or thousands of small plants, of course you're going to make an impact.
“You can leverage an 'economies of unit number' model, which can be defined as a shift from a small number of high-capacity units or facilities to a large number of units or facilities operating at a smaller scale. The good news is that, as we demonstrate in this paper, industrial biomanufacturing can both support and benefit from economies of unit number.”
Gonzalez said developing nations may benefit greatly from decentralised biomanufacturing, and he is even looking farther afield.
“The atmosphere of Mars is 95 percent carbon dioxide, and to plant a flag there, you really have to start with that and solar energy, whether you like it or not,” he said.
“And you can do it with something like I'm describing here.
“You don't need to bring a chemical plant to Mars. You could bring microbes in a vial that replicate and grow and produce what you need from the abundant carbon already there.”
The idea is fleshed-out even further in an article for the journal Science.