Chemicals taken from sawdust (锯屑) and water can knock out more than 99 percent of some disease-causing microbes (微生物). That makes the sawdust mix a potential alternative to current microbe-killing chemicals.
Many disinfectants (消毒剂) used today can harm the environment. They form poisonous by-products when they get washed. Some potentially greener disinfectants exist. They rely on a chemical called “phenol (苯酚)”. But these cleaners can be costly and take a lot of energy to make.
Shicheng Zhang went searching for a better option. He’s an environmental engineer at Fudan University in Shanghai, China. Wood contains many molecules (分子) that look like phenol. So Zhang wondered if microbe-killing chemicals could be obtained from sawdust through a low-cost and low-energy process.
He and his fellow researchers cooked mixtures of water and sawdust for one hour. They heated this sawdust soup under pressure, and then filtered it. Later, they tested how well the liquid killed off microbes. This liquid wiped out E.coli bacteria—microbes that can cause food poisoning. The liquid also killed anthrax bacteria. These microbes cause dangerous infections. What’s more, the disinfectant stopped flu viruses from being infectious.
The researchers also added different amounts of water to the sawdust soup. That let them test how concentrated it had to be to knock out microbes. Depending on its concentration, the mix could kill more than 99 percent of the microbes.
Looking at killed microbes under a microscope revealed some of the ways the sawdust mix kills. The disinfectant damaged the microbes’ cell walls. It also may have messed with the microbes’ proteins and DNA.
Zhang and his fellow researchers didn’t stop at a sawdust disinfectant. They made disinfectants from other plant materials, too. Some of these started as bamboo powder. Others were made using rice plant. Plant materials that are richer in molecules that release phenol-like compounds are best at killing microbes. One example is corn straw.
【小题1】What may be an advantage of Zhang’s sawdust disinfectant over existing ones?| A．Being safer and more effective. |
| B．Being environment-friendly and less expensive. |
| C．Being less expensive and having more lasting effect. |
| D．Being more effective and having more lasting effect. |
| A．The absence of microbes in sawdust. | B．The phenol-like molecules in wood. |
| C．The existence of a greener disinfectant. | D．The possibility of being food poisoned. |
| A．By analyzing data from previous studies. |
| B．By identifying the ways different disinfectants kill. |
| C．By improving the process of dealing with by-products. |
| D．By comparing the effects of different concentrations of the mix. |
| A．A Public Drive Aims to Greener Disinfectants |
| B．A Chinese University Grows Microbe-killing Plants |
| C．A Disinfectant Made from Sawdust Knocks out Microbes |
| D．A Chinese Team Made Breakthroughs in Disease Research |
