Drilling down to the nanometer depths of leaves for biofuels

Jul 19, 2010
A xylem cell with fluorescent lignocellulose bands as the major feature

(PhysOrg.com) -- By imaging the cell walls of a zinnia leaf down to the nanometer scale, energy researchers have a better idea about how to turn plants into biofuels.

In a paper appearing online in the journal Plant Physiology, a team from Lawrence Livermore led by Michael Thelen, in collaboration with researchers from Lawrence Berkeley National Lab and the National Renewable Energy Laboratory, has used four different imaging techniques to systematically drill down deep into the of Zinnia elegans.

Zinnia is a common garden annual plant with solitary daisy like flower heads on long stems and sandpapery, lace shaped leaves. The leaves of seedlings provide a rich source of single cells that are dark green with and can be cultured in liquid for several days at a time. During the culturing process, the cells change in shape to resemble the tube-like cells that carry water from roots to leaves. Known as xylem, these cells hold the bulk of cellulose and lignin in plants, which are both major targets of recent biofuel research.

Using different microscopy methods, the team was able to visualize single cells in detail, cellular substructures, fine-scale organization of the , and even of single zinnia cells, indicating that they contain an abundance of lignocellulose.

"The basic idea is that cellulose is a polymer of sugars, which if released by enzymes, can be converted into alcohols and other chemicals used in alternative ," Thelen said. "But for this to happen efficiently, we need to find ways to see how this is proceeding at several spatial scales."

To get at the sugars is no easy task. The team had to find ways to overcome the hydrophobic protection of crystalline cellulose provided by lignin in the cell wall. The two polymers, collectively called lignocellulose, are very insoluble, resistant to common chemicals and mechanical breakage, and are a superior substance for providing strength and structure to plants.

Image showing a substructure of the cell wall (ring), and the detailed organization of lignocellulose in the cell wall.

The detailed three-dimensional molecular cell wall structure of plants remains poorly understood.

"The capability to image plant cell surfaces at the , together with the corresponding chemical composition, could significantly enhance our understanding of cell wall molecular architecture," said Alex Malkin, a member of the LLNL team who is an expert in atomic force microscopy. "A high resolution structural model is crucial for the successful implementation of new approaches for conversion of biomass to liquid fuels."

To make fuels from plant biomass requires a thorough understanding of the organization of cell walls before determining the best methods for cell wall deconstruction into its components. Catherine Lacayo, a postdoctoral scientist working with Thelen and Malkin, has taken the first steps toward a comprehensive approach.

She came up with techniques that reveal the inner structure of cell walls in these single xylem cells, which represent about 70 percent of the cellulose in plants that can be used in fuel processing. "This approach will be useful for evaluating the responses of plant material to various chemical and enzymatic treatments, and could accelerate the current efforts in lignocellulosic biofuel production."

Explore further: Study on pesticides in lab rat feed causes a stir

Related Stories

Advance in understanding cellulose synthesis

Jun 14, 2009

Cellulose is a fibrous molecule that makes up plant cell walls, gives plants shape and form and is a target of renewable, plant-based biofuels research. But how it forms, and thus how it can be modified to design energy-rich ...

Protein power for Jack and the beanstalk

May 17, 2010

Plant geneticists are on a determined quest -- to control auxin, a powerful plant growth hormone. Auxin tells plants how to grow, where to lay down roots, how to make tissues, and how to respond to light and gravity. Knowing ...

Formation of cellulose fibers tracked for the first time

Apr 20, 2006

Cellulose--a fibrous molecule found in all plants--is the most abundant biological material on Earth. It is also a favored target of renewable, plant-based biofuels research. Despite overwhelming interest, ...

Scaling the Plant Cell Wall

Feb 14, 2005

Scientists are one step closer to understanding how plants synthesize the fibrous carbohydrates that make up their cell walls. Cell-wall polysaccharides, as they are known, constitute a major source of dietary fiber and ...

Recommended for you

Study on pesticides in lab rat feed causes a stir

21 hours ago

French scientists published evidence Thursday of pesticide contamination of lab rat feed which they said discredited historic toxicity studies, though commentators questioned the analysis.

International consortium to study plant fertility evolution

Jul 02, 2015

Mark Johnson, associate professor of biology, has joined a consortium of seven other researchers in four European countries to develop the fullest understanding yet of how fertilization evolved in flowering plants. The research, ...

Making the biofuels process safer for microbes

Jul 02, 2015

A team of investigators at the University of Wisconsin-Madison and Michigan State University have created a process for making the work environment less toxic—literally—for the organisms that do the heavy ...

Why GM food is so hard to sell to a wary public

Jul 02, 2015

Whether commanding the attention of rock star Neil Young or apparently being supported by the former head of Greenpeace, genetically modified food is almost always in the news – and often in a negative ...

The hidden treasure in RNA-seq

Jul 01, 2015

Michael Stadler and his team at the Friedrich Miescher institute for Biomedical Research (FMI) have developed a novel computational approach to analyze RNA-seq data. By comparing intronic and exonic RNA reads, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.