Capitol News

What do poplar trees, sharks, and biofuels have in common? While it might sound like a riddle, a team led by Michigan State University biochemists has reported findings concerning all three in the quest for cleaner energy.

Appearing in the Plant Biotechnology Journal, the team's latest paper explores how poplar trees can be engineered to produce a highly valuable chemical commonly obtained from shark livers. Engineering poplars to produce this chemical would greatly boost their economic viability as an already-promising source of biofuels and help cut back destructive shark harvesting.

"I think this project really highlights how we can use industrial crops in new ways," said Jake Bibik, first author on the paper and a former doctoral student in the lab of Michigan State researcher Björn Hamberger.

Michigan State University's Björn Hamberger is an expert in specialized metabolites known as terpenes. These compounds have long been used by humanity for their medicinal, cosmetic, and flavoring properties. "Using engineered, nonfood crops like poplar may provide a more sustainable alternative for generating chemicals typically derived from fossil fuels or even new specialty chemicals altogether."

On their own, poplars check several boxes needed to be a successful biofuel feedstock. They grow quickly on land not used for agriculture, and their biomass — the organic material where energy is stored — can be deconstructed and fermented for biofuel production.

One of the biggest challenges comes down to simple economics. "Biofuels are still not competitive against the cheap petrochemistry that’s out there," said Hamberger, a James K. Billman Endowed Professor in the College of Natural Science’s Department of Biochemistry and Molecular Biology.

Hamberger is also a co-investigator at the Great Lakes Bioenergy Research Center (GLBRC), a U.S. Department of Energy-funded bioenergy research facility led by the University of Wisconsin–Madison. GLBRC scientists have long sought ways to extract other high-value products from biomass. Research has shown that poplar can be a viable source of p-aminophenol, which is used to make dyes, adhesives, and other polymers, as well as paracetamol, the active ingredient in Tylenol.

When Hamberger joined the center in 2015, he suggested going after terpenes — chemical compounds plants use in unique environmental interactions such as attracting pollinators or defending against pests.

"Terpenes are the oldest, largest class of specialized metabolites on the planet," said Hamberger. "Since they’re important for all sorts of interactions, it’s driven their diversity to a spectacular point where the chemistry out there is just mind-blowing."

Used by humans for millennia, terpenes have been shown to possess anti-inflammatory, antimicrobial, anticancer and antibacterial properties and are key components in flavorings, cosmetics and perfumes among other applications.

Bibik, Hamberger and their collaborators were targeting squalene — an organic compound widely used in cosmetic products and crucial component in vaccines. Today most squalene comes from shark liver; indeed its name originates from Latin word for shark: squalus.

During this project team engineered poplars along two distinct chemical pathways producing squalene: one utilized cytosol found inside cells while another sought production within chloroplasts responsible photosynthesis.

“By diverting carbon away from regular metabolism making specialized chemicals unique tissues droplets employing innovative strategy turning trees into biological factories,” said Professor Shawn Mansfield University British Columbia expert transformation collaborator latest paper.“It’s exciting part highly novel forward-thinking project.”

While cytosol pathway discovered interfere root formation chloroplast route resulted production 0.63 milligrams per gram leaves.With promising result time what called “reality check.”

Working Christos Maravelias professor chemical biological engineering Princeton University team next performed analysis determine minimum sales price produced sold break even.Researchers found number $144 kilogram.Shark-derived comes $40 kilogram.“If want sell green product customer can’t only green needs affordable,” said.“Luckily several ways boost value.One increasing overall production brings cool world perfumes another marine animal product ambergris.”Produced digestive system sperm whales ambergris prolong scents.Hamberger possible “upgrade” ambrein another high-value makes ambergris.Scientists demonstrated bacteria engineered paving further investigation could same.Furthermore collaborator Tom Sharkey showed emit less isoprene gas indirectly contributes greenhouse effect.“Jake colleagues working method perhaps greatest promise make specialty chemicals fuel liquid fuel jet airplane travel,” said Distinguished affiliated MSU-Department Energy Plant Research Laboratory Plant Resilience Institute collective findings researchers broken new ground transforming attractive source valuable compounds.Bibik now senior scientist biotechnology company MelaTech ultimately step leveraging biochemical diversity address greatest challenges.“I think work contributes growing foundation necessary translate plant engineering terpenoid research meaningful biotechnologies.”