Active or Passive Voice in International research journal, within the field of microorganism?
The choice between active and passive voice is mainly a matter of taste. As a writer, you are entitled to a certain degree of liberty in your stylistic choices. Even within the generally tight constraints of scientific and academic writing, there is no established dogma on passive vs. active voice, and you will find people advocating (some very strongly) both for and against the use of the passive voice.

Duke’s Graduate School Scientific Writing Resource has a good summary of the pros and cons of passive and active voices. In particular, it lists the position advocated in some high-level style guides, editorials, and other essays of note.

I think the current trend is toward a diminution of use of the passive voice. The reasons are summed up nicely by Randy Moore (The American biology teacher):


  Most scientists use passive voice either out of habit or to make themselves seem scholarly, objective or sophisticated. Scientists have not always written in passive voice. First-person pronouns such as I and we began to disappear from scientific writing in the United States in the 1920s when active voice was replaced by today's inflexible, impersonal and often boring style of scientific writing.


The main argument used in favour of passive voice is that it promotes objective statements, rather than focusing on the actor. However, removing the mention of the actor in the text does not actually prevent subjectivity in the experiments: even if I write “the sample was smeared until it reached a thickness of 1 µm”, somewhat actually did smear the sample (and could have screwed it by going too slow or too fast). So the counter-argument is that passive voice does not promote objectivity, but only the appearance of objectivity.

The main argument in favour of active voice is that it makes for shorter, clearer, less boring text.



I love that anecdote from Rupert Sheldrake (School Science Review):


  “The test tube was carefully smelled.” I was astonished to read this sentence in my 11-year-old son's science notebook. At primary school his science reports had been lively and vivid. But when he moved to secondary school they became stilted and artificial.