Exceptions: PAHs found in space dust, or other extreme examples.

And from this definition it is easy to see that 'humic substance' is not a molecule at all, it's a material. (made from a diverse collection of transformed molecules)

Albert Waksman described it as such back in the 1920s and 30s (!)

Reading a paper that refers to a certain 'biomolecule'. What an odd word. The vast majority of molecules (apart from simple gases) are biological in origin. Even the synthetic ones, as they are mostly made of fossil materials (in turn, mostly transformed primitive tree bark/algal cells).

It's like running into an old friend.

And reading new papers that cite the legends is like "oh, hello, new friend?"

The good news is that one hour in the lab will yield the answers you need 😊

Even more exciting, the same methods help you assess the quality of hard carbon, opening up a world of possibilities for 21st century products and materials.

Chemistry + Biology provides the best resource efficiency.

But seeing as the full suite of inter-molecular interactions occur (complex H-bonding, pi-stacking, charge interactions, transient ether bonds, metal complexation etc etc) it's clear to see why this 'molecule' has not been resolved. (not a molecule, a material!)

And arguments around molecular size remind me of the humus debate! If humus was easy to characterize as a polymer or a macromolecule then there wouldn't be so much argument.

And yes, to be an enzyme, catalysis needs to be facilitated. But do siderophores fit here? depending on how they are used by the organism?? Fun to contemplate things that don't fit in neat boxes anyhow.

It follows that this one indicator is insufficient to rank different compost batches. If you know the history of inputs and process controls it’s a great indicator but can also hide some issues (lack of complete maturation). Most of the standard indicators have this problem, so you need multiple.

There is much to be gained by remembering their huge head start, evolutionarily speaking. If you try and take the perspective of the microbe then you start to appreciate the metabolic diversity and why they have extensive genomes that produce a very useful array of chemistry.

This is a useful generalization (not an absolute), BUT the downside is that it casts microbial degraders in the service of plants or higher organisms. As if they are more like hardy automatons that exist solely to clean up the excess.

I was recently re-reviewing a piece supposedly on soil advocacy (from a non-scientist). As per usual, microbes got the obligatory mention as degraders. But first they found it necessary to mention that all chemical energy on our Earth comes via the sun via photosynthesis.

Why is this important? The diversity of microbial metabolism (even in everyday environments) deserves more credit.

One part I paid attention to was the time gap between a banded iron formation in Sudan and the oxygenation of our atmosphere, a gap of 300 MILLION years!

We still know so little about how bacterial metabolism really works.

Perhaps oddly, the announcement of the Nobel prize on MOFs prompted me to think of all the wonderful ways microbes have learnt to harness materials to their advantage.