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Feature Story September 2010 |
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table of contents>Ten from ’10 | < Back|1|2|3|4|6|7|8|9|10|11|Next > |
Ten from ’10 continuedShreya Shrestha, biology
Thesis Closeup:Growing Biodegradable Plastic.In 1925, a French researcher named Maurice Lemoigne discovered that certain bacteria are capable of manufacturing plastic, in particular a polymer known as poly(3-hydroxybutyrate) or PHB. This finding aroused scant interest at the time, but decades later—with the planet awash in plastic pollution—this discovery gained enormous significance, because PHB is biodegradable. In recent years, researchers have transferred the PHB-making genes from bacteria into various crops such as peas, potatoes, sugar cane, and tobacco, searching for a practical way to produce PHB. One promising plant is the poplar tree. Poplars can be engineered to manufacture PHB in their leaves, which can be harvested without harming the trees themselves. With a biomass larger than any other PHB-making plants to date, poplars could produce a high and economically viable yield. One drawback with using plants to make PHB is that their growth is typically impaired due to the diversion of their resources towards making the plastic. Shreya investigated the effects of inserting a novel inducible promoter—an on-off switch—into poplar saplings so that PHB production can be turned off while the tree is growing, then turned on when it has reached maturity. Raising 144 saplings in the biology department’s greenhouse, she found that within the two groups of poplars studied, PHB production using the on/off switch didn’t slow the plants’ growth. (To be economically viable, approximately 12 percent of the leaves’ dry weight should consist of PHB.)—CL |
table of contents>Ten from ’10 | < Back|1|2|3|4|6|7|8|9|10|11|Next > |
September 2010 |