The reading passage talks about a new kind of material called biopolymers which can be used to make plastic goods. However, the merits stated in the reading passage turn out to be not so good in the lecture.
First, the written material says that the material is easier to decompose than those old oil-based plastic bags, which easily become rubbish and is a disaster to the environment. However, the lecturer didn't think so. The professor asserted that the decomposition takes place only under certain circumstances and some of the requirements are hard to meet. Those conditions include consistant heat for an entire week. Without heat and moisture, it takes almost the same time to decompose as traditional plastic.
Secondly, the reading suggests that the material saves energy and is environmental friendly. But the professor doubted it because corns must be planted at first in order to make biopolymers and the process of corn-planting actually consumes a lot of energy and is never good for the environment. The lecturer remarked that the use of pesticide and other chemicals simply exchange the air pollution with the water pollution.
Lastly, the quality of the new material is said to be ,if not better than, as good as those oil-based plastic in the reading passage. And the lecturer had a totally different opinion. She held that the new material is inferior to the old fashioned plastic. For instance, if one wants to use the new plastic to store things like CDs, the container must be durable. But biopolymers will decompose under conditions of high heat and moisture and is thus not that durable.
In sum, the lecturer did not believe in the advantages given in the passage and held that those advantages of the new material are actually limitations of it.