How bacteria bred in Montana will fortify the bread of Egypt
Today is scheduled to be baladi day in Cairo. Officials selected this day to distribute a new strain of bacteria for fermenting Egypt's baladi bread -- a strain that will substantially boost its nutritional punch. This is one of the most significant developments in the history of this food staple.
It also points up the value of understanding more about the roles that the lowly one-celled plants classified as bacteria play in the world today. They are important in such diverse areas as nutrition and rainfall. In the latter case, bacteria may be important cloud-seeding agents needed to form rain. Loss of such bacteria due to overgrazing may have contributed to the drought that has afflicted parts of Africa.
The bacterium being distributed in Cairo -- a strain of Lactobacillus fermentum -- was bred at Montana State University from samples of bacteria used in Egypt to ferment baladi bread. David Sands and co-workers have worked for nearly three years to develop the strain as a commercially useful fermentation agent.
The problem with baladi, a wheat bread, and many other grain products is that they lack a full complement of amino acids, the protein building blocks that are needed for human nutrition. Grains are a rich source of proteins. But this protein is generally short on the amino acid lysine. This is why the cereals are not as good, nutritionally, as meat, whose proteins contain a full amino acid complement.
The Montana bacteria have been bred for lysine production. When they are used to ferment baladi, the bread has a protein quality as good as that of meat. This can make a major contribution to the diet of Egyptians and of other protein-short people.
Sands notes that merely enhancing a food's nutritional quality is only part of the hunger-fighter's job. The food must also retain its traditional taste and texture if it is to be accepted and eaten regularly. Protein supplements such as soy flour change bread taste, he says. But bread made with the new bacteria is just like the ``old fashioned'' product. ``We've been very subversive,'' Sands says. ``You can't tell the difference. It tastes just the same.''
He adds that the new bacterial strain is very stable. The organisms can be added either to wheat flour or to the grain before it is milled. The bread is produced from a starter that is allowed to ferment overnight -- as is done in making sourdough bread. During the fermentation, the bacteria multiply rapidly, producing large amounts of lysine as well as lactic acid, which contributes to the bread's distinctive taste.
The Montana scientists -- Sands, Rosemary Newman, and Walt Newman -- have worked with Mohamed Eid, a visiting scientist from Egypt. Together, they brought the bacteria to the point where it is ready for distribution. It also can be used in yeast breads and should find wide application, especially in food-short countries.
Sands is interested in more than food as he investigates third-world bacteria. He is especially interested in their connection with rainfall.
Rain forms around ice crystals in clouds. And these crystals form around what meteorologists call ice nuclei. Sands says he believes bacteria are such nuclei. Further, the loss of ice-nucleating bacteria due to overgrazng of vegetation may reinforce the African drought, he says.
Rainmaking bacteria need to be up on plants, on leaves, to disperse properly into the air. Remove the vegetation and you suppress the bacterial seeding. Sands is organizing a research team to investigate the drought-bioprecipitation link in the field in Africa.
Russell C. Schnell of the National Oceanic and Atmospheric Administration, who has pioneered the study of bacteria as ``cloud seeders,'' warns that the role of bacteria in rainfall has yet to be proved. He calls the link ``plausible,'' though.
Moreover, he adds, many indications have been found that either bacteria exude ice-forming nuclei or their bodies are themselves nucleating agents.
Schnell explains that, all over the world, only two kinds of bacteria appear to be involved in rainmaking -- Pseudomonas syringae and Erwinia herbicola. The first of these is also the type of bacteria involved in frost formation on plants.
Steven Lindow and Nicholas Panopoulos of the University of California at Berkeley have used genetic engineering to remove the gene that enables these bacteria to produce the ice-nucleating protein that stimulates frost-crystal formation.
This is the experiment whose field test has been held up by federal court order pending the filing of a satisfactory environmental-impact statement.
The suit leading to this injunction, which was brought by activist Jeremy Rifkin and others, cited concern that the altered bacteria might spread and affect rainfall as one reason for seeking an injunction against the field test.
Bacteria are ubiquitous on our planet. Some are harmful. Many are useful, and even essential, in maintaining a healthy environment. But the full range of their importance as a basic terrestrial life form is still poorly known.
A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.