Abstract
I still remember the confusion in my mind when, in 1992, as a first-year PhD student, I attended the 7th C1-meeting at the University of Warwick. I was working with methanol and methane oxidizers and several times speakers in the conference used the word heterotroph to quickly describe non-methylotrophic organisms or non-methylotrophic metabolism within facultative methylotrophs. Based on my first-degree knowledge, I was pretty sure the bugs I was studying were heterotrophic, but I humbly thought I had a lot to learn and that my doubts would be solved by reading more about the subject. However, a few years later now, after making some order in the facts about the types of methylotrophic metabolism that have been described, I am sure that heterotroph is not the antonym (word of opposite meaning) of methylotroph, and that my original sense of confusion was not caused by my ignorance.