Sunday, January 9, 2011

Biocatalysis - Has the Time For Using Bio-Based Processes Finally Arrived?

Biocatalysis-the use of enzymes to catalyze a chemical reaction-has become a scientific buzz word. To be clear, a biocatalyst can be one or more enzymes or cells-living, dormant, or dead-and the reaction can be a single chemical reaction or series of reactions. Thus, biocatalysis includes the one-step enzymatic production of aspartic acid (a component of the non-caloric sweetener aspartame), the two-step oxidation of ethanol to acetic acid (vinegar can be made this way, and if it is, it is called natural), and the multi-step brewing of beer (quite likely the oldest example of biocatalysis, with historical records dating back 6000 years!). Proponents say biocatalysis is green and sustainable. Critics will tell you that it is often costly and requires a development timeline that is too long to meet the needs of real world industrial manufacturing. What is the reality?

At the outset it is important to point out that biocatalysis is not a panacea, and never will be, and I say this as an evangelist for biocatalysis. There are both pros and cons for the use of biocatalysis as compared to more traditional chemical catalysis. As a catalyst, a biocatalyst does what any catalyst can do: increases the rate at which a chemical reaction takes place, but does not affect the thermodynamics of the reaction. To take maximum advantage of biocatalysis, we need to understand what biocatalysts do well, and equally what they do poorly, and then seek to implement biocatalysts in processes that benefit from their advantages.


One of the most important advantages of biocatalysts is high selectivity, manifested as stereo-selectivity (for chiral synthesis or separation, often used for the synthesis of pharmaceutical intermediates in which only one stereoisomer possesses the desired biological activity), positional selectivity (also known as regio-selectivity, allowing selective modification of a specific site in a molecule), and functional group selectivity (i.e. chemo-selectivity, allowing one type of chemical functional group to be modified in the presence of another, sometimes more reactive functional group).

Biocatalysis - Has the Time For Using Bio-Based Processes Finally Arrived?

Such selectivity is highly desirable in chemical synthesis, offering benefits such as higher yields, fewer side reactions, elimination of protection and de-protection steps, purer products, easier recovery and separation, and reduced environmental waste. There are also operational advantages, including the ability to carry out reactions under mild operational conditions, avoiding extremes of pH, temperature, and pressure that often require the use of expensive equipment or energy intensive processing. Biocatalytic processes also rely on catalysts that are biodegradable and are produced from renewable resources, meaning the processes are typically "greener" and more sustainable. Since there is an enzymatic counterpart to most known chemical reactions, the potential scope for the application of biocatalysis is broad.

Practically speaking, however, this breadth of scope in the chemical industry has not been realized. Presently, I estimate that well over 100 different biocatalytic processes are implemented in pharmaceutical, chemical, agricultural, and food industries, which may at first glance seem considerable. However, this represents only a small fraction of the processes developed and carried out currently. Enzymes have not yet been developed to cover as broad a spectrum of chemical reactions as have chemo-catalysts. Researchers in both academia and companies are working to overcome this limitation, but it will take time.

Speed of process development is also often slower for biocatalytic processes than their chemical counterparts, in part due to the lack of experience that chemists have with the use of enzymes and microbial cells. Modern biotechnological tools now allow enzymes to be significantly improved-optimized-for a desired reaction, but this optimization is often too costly and time-consuming to meet tight timelines; therefore, broad application remains elusive. By focusing now on those reactions where enzymatic alternatives are already well-developed, honing our expertise in using biocatalysis, and staying abreast of future developments that will bring a wider range of practical biocatalytic alternatives, we can choose wisely where to invest resources to maximize the value of this rapidly developing technology.

Biocatalysis - Has the Time For Using Bio-Based Processes Finally Arrived?PRETTY FACE! (Opening Mail: Day 594) Video Clips. Duration : 18.72 Mins.

THIS ISN'T TODAY'S VLOG. READ HERE - You guys asked to show more clips of the mail we get being opened, however - since there is so much of it you said we should put it in a separate video. That way we can show more stuff! Please remember guys, you DON'T need to spend money on us! We love artwork, letters just as much! Please save your money for yourself! :) Today's vlog (Day 594) can be seen by clicking here:

Keywords: charlestrippy, internet, killed, television, tv, alli, zoey, marley, ctfxc, hot, topic, eskimo, kiss, kisses, cute, cold, tron, premier, la, hollywood, times, square, mtv, new, years, canon, iphone, 7d, typing, android, nose, puppy, dogs, dog, trick, zombie, university, fsu, epic, snow, snowball, fight, face, googletv, contest, idiot, drops, huge, gingerbread, house, ateam

David Rozzell maintains a web site and blog dedicated to the latest developments and news in biofuels, biocatalysis, and industrial applications of biotechnology at Contact him at

No comments:

Post a Comment