Featured Research

from universities, journals, and other organizations

New hydrolysis model promising tool in cellulosic biofuel studies

Date:
July 26, 2010
Source:
University of California - Berkeley
Summary:
Chemical engineers have come up with an improved model for how cellulase enzymes degrade cellulose, a critical step in liberating sugars that can be fermented into biofuels. The researchers have created a mechanistic model that should provide a better understanding of the breakdown mechanisms, allow more directed and rational approaches to engineering effective enzymes, and improve the overall process of hydrolysis.

Scientists are working hard to develop the tools and find the organisms to break down the complex structure of plant cellulose into its component sugars -- the key step toward fermentation of those sugars into usable biofuel. This process needs to be simple and economically efficient before cellulosic biofuels can compete with fossil fuels for transportation energy use.

Related Articles


As with any exploration of systems that involve largely unknown processes, a mechanistic model can be an important first step in improved understanding. Researchers at the Energy Biosciences Institute's (EBI) laboratories on the University of California, Berkeley, campus have improved that step, bringing science closer than ever before to predicting the deconstruction activity of enzymes towards cellulose.

In a paper recently accepted by the journal Biotechnology and Bioengineering, four EBI scientists at UC Berkeley -- chemical engineering faculty members Doug Clark and Harvey Blanch, postdoctoral researcher Seth Levine and graduate student Jerome Fox -- detail their analysis that led to the most specific model to date of the enzymatic hydrolysis of cellulose.

"It's a first step in being able to have a detailed picture of what happens between cellulases (enzyme mixtures with complementary activities) and the substrate (cellulose)," said lead author Levine. Through this better understanding of the breakdown mechanisms, he said, more directed and rational approaches can be taken to engineer effective enzymes and improve the overall process of hydrolysis.

Much of the action happens at the surface of a substance like cellulose, the fibrous polysaccharide in the plant cell wall composed of hydrogen-bonded chains of the sugar glucose. Levine likens the surface to a "black box," where multiple shapes and unknown features of particles add to the complicated nature of the reactions there. Previous models relied on simple, sometimes overly broad assumptions and explained little about the chemical and physical reactions occurring there, he said.

With the EBI's latest methodology, the mechanisms by which cellulases trigger the hydrolysis of cellulose were delineated in three steps -- adsorption, complexation (molecular bonding) and reaction. The researchers discovered that the amount of surface area was critical for the activities of enzymes and for how well they work together in combination.

"The model explicitly tracks individual cellulases and key cellulose surface properties," the paper concludes. "Independent enzyme adsorption and complexation steps have been incorporated in an attempt to capture the most important details of the enzyme-substrate interaction. The model results illustrate the importance of understanding the effect of relevant surface areas to enzyme hydrolysis activity."

One phenomenon they tracked was the typical decline in the sugar breakdown rates after an initial "burst" phase, a reaction that usually leads to longer processing and greater enzyme loads, a costly and time-consuming step. Their research revealed a mix of surface area, structural changes within the surface, and cellulase interactivity during hydrolysis as major contributors to the slowdown. Further refinement of the model in future investigations should uncover more details.

"This work confirms that despite the complexity, enzymatic hydrolysis of cellulose is amenable to modeling," said Clark, the principal investigator for the EBI program on "Bioprocess Optimization from Cellulose Hydrolysis to Product Fermentation." "It also shows the importance of surface area, which we can control through pre-treatment (of the cellulose). There are now a lot of levers we can play with in finding an optimal enzymatic route to break cellulose down into sugars that can be converted to fuels."

Though many unknowns still remain in deciphering the complicated process that extracts sugars from plant cellulose, the EBI's mechanistic model adds a significant tool to the scientist's kit.


Story Source:

The above story is based on materials provided by University of California - Berkeley. Note: Materials may be edited for content and length.


Journal Reference:

  1. Seth E. Levine, Jerome M. Fox, Harvey W. Blanch, Douglas S. Clark. A mechanistic model of the enzymatic hydrolysis of cellulose. Biotechnology and Bioengineering, 2010; DOI: 10.1002/bit.22789

Cite This Page:

University of California - Berkeley. "New hydrolysis model promising tool in cellulosic biofuel studies." ScienceDaily. ScienceDaily, 26 July 2010. <www.sciencedaily.com/releases/2010/07/100726094913.htm>.
University of California - Berkeley. (2010, July 26). New hydrolysis model promising tool in cellulosic biofuel studies. ScienceDaily. Retrieved April 20, 2015 from www.sciencedaily.com/releases/2010/07/100726094913.htm
University of California - Berkeley. "New hydrolysis model promising tool in cellulosic biofuel studies." ScienceDaily. www.sciencedaily.com/releases/2010/07/100726094913.htm (accessed April 20, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, April 20, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Humanoid Robot Can Recognise and Interact With People

Humanoid Robot Can Recognise and Interact With People

Reuters - Innovations Video Online (Apr. 20, 2015) — An ultra-realistic humanoid robot called &apos;Han&apos; recognises and interprets people&apos;s facial expressions and can even hold simple conversations. Developers Hanson Robotics hope androids like Han could have uses in hospitality and health care industries where face-to-face communication is vital. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Drones and Health Apps at Santiago's "Robotics Day"

Drones and Health Apps at Santiago's "Robotics Day"

AFP (Apr. 20, 2015) — Latin American robotics experts gather in Santiago, Chile for "Robotics Day". Video provided by AFP
Powered by NewsLook.com
Japan Humanoid Robot Receives Customers at Department Store

Japan Humanoid Robot Receives Customers at Department Store

AFP (Apr. 20, 2015) — She can smile, she can sing and she can give you guidance at one of the most upscale department stores in Tokyo...a female-looking humanoid makes her debut as a receptionist Video provided by AFP
Powered by NewsLook.com
Pee-Power Toilet to Light Up Disaster Zones

Pee-Power Toilet to Light Up Disaster Zones

Reuters - Innovations Video Online (Apr. 20, 2015) — Students and staff are being asked to use a prototype urinal to &apos;donate&apos; urine to fuel microbial fuel cell (MFC) stacks that generate electricity to power lighting. The developers hope the pee-power technology will light toilet cubicles in refugee camps, where women are often at risk of assault in poorly lit sanitation areas. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins