ENZYME ZAPS PEROXIDE
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NEWS F THE WEEK GREEN CHEMISTRY ΕΝΖΥΜΕ ZAPS PEROXIDE Heat- and alkali-stable catalase removes H 2 0 2 from process water NO DIVING Hot spring pool at Yellowstone National Park where catalase- containing thermophilic bacterium was found. A CATALASE FOUND IN A Mi- crobe from a hot spring in Yellowstone National Park could help make industrial bleaching processes more envi- ronmentally benign. Industries have turned increasingly to hydrogen peroxide as an alterna- tive to toxic chlorine for bleaching paper, tex- tiles, and other products. Perox- ide is much less hazardous than chlorine, but there's still a need for better ways to remove perox- ide so process water can be reused or returned to the environment. Currently process peroxide is either diluted with large quanti- ties of clean water, which is ex- pensive and wasteful, or it is treat- ed with agents like sodium bisulfite or hydrosulfite, which leaves salt in the water. Catalases promote the conversion of hy- drogen peroxide into water and oxygen, but peroxide-based in- dustrial bleaching processes are carried out at elevated tempera- tures and alkaline pH levels— conditions that cause the catalases that are currently available com- mercially to break down quickly Chemical engineer Vicki S. Thompson and biologists Kastli IMMIGRATION POLICY Scientists And Other Academics Invited To Help Speed Up Visa Approval Process T he Department of Homeland Security (DHS), in con- sultation with the State Department, last week launched the U.S.-VISIT (U.S. Visitor & Immigrant Sta- tus Indicator Technology) program, an automated system to collect, maintain, and share information on foreign nation- als. It is expected to be in place at air- and seaports by the end of the year. In written remarks about the system, DHS Undersecre- tary Asa Hutchinson said: "We've also invited experts from science and academia to help us speed up the visa approval process for foreign scholars and teachers who clearly pose no threat. We welcome students, visitors, and business travelers." SCRUTINY Immigrants wait outside the Immigration & Naturalization Services building in Los Angeles. Under the new program, "DHS will, for the first time, oversee the visa issuance process," Hutchinson said. "We will be responsible for maintaining its integrity, working through and with the consular offices of the U.S. State Department." Meanwhile, a State Department spokesman says that, contrary to some reports, the depart- ment is not preparing to conduct face-to-face interviews with all applicants for a U.S. visa. DHS Secretary Tom Ridge has said that U.S.-VISIT will be capable of scanning travel docu- ments and taking fingerprints and pictures of foreign nationals. The use of other biométrie iden- tifiers, such as facial recognition and iris scan, is still being studied.—WILLIAM SCHULZ D. Schaller and William A. Apel of the Department of Energy's Idaho National Engineering & Environmental Laboratory (IN- EEL), in Idaho Falls, have nowpu- rified and characterized a new catalase from a thermophilic bac- terium from a 'Yellowstone hot sprmg[Biotechnol. Prog, published online May 15, http://dx.doi.org/ 10.1021/bp034040t}. The new enzyme is much more stable than previously known catalases, and it is compatible with high-tem- perature alkaline conditions. Chemistry professor Terrence J. Collins, director of the Insti- tute for Green Oxidation Chem- istry at Carnegie Mellon Univer- sity, comments that the study "represents an outstanding piece of scientific detective work, analysis, and discovery The en- zyme exhibits exceptional com- mercially significant properties in its pronounced thermal stabil- ity and its tolerance of mildly ba- sic conditions, such as are often found in peroxide-based indus- trial processes." It could eliminate "in a technically ideal way one of the few environmental downsides associated with hydrogen perox- ide technologies." The new catalase has a half- life of about 15 days at 70 °C and pH 10—conditions commonly encountered in industrial bleach- ing processes. Commercially avail- able catalases last just 15 to 20 minutes under such conditions. At 70 °C and pH 11, the stabil- ity of the new catalase "was dras- tically reduced, with complete loss of activity after 30 minutes," the researchers write. That lowers its utility, Collins notes, "but it is al- most certainly not a fatal flaw." The INEEL team now hopes to generate larger amounts of en- zyme, attach it to polymer beads, and pack the beads into columns that can be used to filter peroxide from industrial wastewater. This is "probably doable," Collins says, "and it would represent an excel- lent achievement ifit can be done cost-effectively—which is like- ly"-STU BORMAN 8 C&EN / MAY 26, 2003 HTTP://WWW.CEN-ONLINE.ORG IDAHO NATIONAL ENGINEERING & ENVIRONMENTAL LAB PHOTO
Transcript of ENZYME ZAPS PEROXIDE
NEWS F THE WEEK G R E E N C H E M I S T R Y
ΕΝΖΥΜΕ ZAPS PEROXIDE Heat- and alkali-stable catalase removes H 2 0 2 from process water
NO DIV ING Hot spring pool at Yellowstone National Park where catalase-containing thermophilic bacterium was found.
A CATALASE FOUND IN A Microbe from a hot spring in Yellowstone National Park
could help make industrial bleaching processes more environmentally benign.
Industries have turned increasingly to hydrogen peroxide as an alternative to toxic
chlorine for bleaching paper, textiles, and other products. Peroxide is much less hazardous than chlorine, but there's still a need for better ways to remove peroxide so process water can be reused
or returned to the environment. Currently process peroxide is
either diluted with large quantities of clean water, which is expensive and wasteful, or it is treated with agents like sodium bisulfite or hydrosulfite, which leaves salt in the water. Catalases promote the conversion of hydrogen peroxide into water and oxygen, but peroxide-based industrial bleaching processes are carried out at elevated temperatures and alkaline p H levels— conditions that cause the catalases that are currently available commercially to break down quickly
Chemical engineer Vicki S. Thompson and biologists Kastli
I M M I G R A T I O N P O L I C Y
Scientists And Other Academics Invited To Help Speed Up Visa Approval Process
T he Department of Homeland Security (DHS), in consultation with the State Department, last week launched the U.S.-VISIT (U.S. Visitor & Immigrant Sta
tus Indicator Technology) program, an automated system to collect, maintain, and share information on foreign nationals. It is expected to be in place at air- and seaports by the end of the year.
In written remarks about the system, DHS Undersecretary Asa Hutchinson said: "We've also invited experts from science and academia to help us speed up the visa approval process for foreign scholars and teachers who clearly pose no threat. We welcome students, visitors, and business travelers."
S C R U T I N Y Immigrants wait outside the Immigration & Naturalization Services building in Los Angeles.
Under the new program, "DHS will, for the first time, oversee the visa issuance process," Hutchinson said. "We will be responsible for maintaining its integrity, working through and with the consular offices of the U.S. State Department."
Meanwhile, a State Department spokesman says that, contrary to some reports, the department is not preparing to conduct face-to-face interviews with all applicants for a U.S. visa.
DHS Secretary Tom Ridge has said that U.S.-VISIT will be capable of scanning travel documents and taking fingerprints and pictures of foreign nationals. The use of other biométrie identifiers, such as facial recognition and iris scan, is still being studied.—WILLIAM SCHULZ
D. Schaller and William A. Apel of the Department of Energy's Idaho National Engineering & Environmental Laboratory (IN-EEL), in Idaho Falls, have nowpu-rified and characterized a new catalase from a thermophilic bacterium from a 'Yellowstone hot sprmg[Biotechnol. Prog, published online May 15, http://dx.doi.org/ 10.1021/bp034040t}. The new enzyme is much more stable than previously known catalases, and it is compatible with high-temperature alkaline conditions.
Chemistry professor Terrence J. Collins, director of the Institute for Green Oxidation Chemistry at Carnegie Mellon University, comments that the study "represents an outstanding piece of scientific detective work, analysis, and discovery The enzyme exhibits exceptional commercially significant properties in its pronounced thermal stability and its tolerance of mildly basic conditions, such as are often found in peroxide-based industrial processes." It could eliminate "in a technically ideal way one of the few environmental downsides associated with hydrogen peroxide technologies."
The new catalase has a half-life of about 15 days at 70 °C and pH 10—conditions commonly encountered in industrial bleaching processes. Commercially available catalases last just 15 to 20 minutes under such conditions.
At 70 °C and pH 11, the stability of the new catalase "was drastically reduced, with complete loss of activity after 30 minutes," the researchers write. That lowers its utility, Collins notes, "but it is almost certainly not a fatal flaw."
The INEEL team now hopes to generate larger amounts of enzyme, attach it to polymer beads, and pack the beads into columns that can be used to filter peroxide from industrial wastewater. This is "probably doable," Collins says, "and it would represent an excellent achievement if it can be done cost-effectively—which is like-ly"-STU BORMAN
8 C&EN / MAY 26, 2003 H T T P : / / W W W . C E N - O N L I N E . O R G
IDAHO NATIONAL ENGINEERING & ENVIRONMENTAL LAB PHOTO
