Guar gum, a plant colloid, costs less than agar and is better suited for growing thermophilic bacteria, but is also more difficult to handle, being more viscous and less transparent. The bacterial polysaccharide xanthan is cheaper as well but forms weaker jellies that, as with carrageenan, might result in puncturing its surface. Other colloids, like alginate (from brown seaweed) and gellan gum (from a bacterium), don’t set solely based on temperature and require additives for gelation. These additives might interfere with microbial growth and make the preparation of those jellies less handy than agar plates.
这种重资产模式在初期投入巨大，但在价格战进入白热化的阶段，它便构成了难以复制的成本护城河。
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（一）居民会议或者居民代表会议讨论决定的事项及其实施情况；
这100家企业最不吝研发，零盈利也敢拼