Lab M: Agar No. 1 Bacteriological General Purpose, Agar No.2 Bacteriological High Clarity.
Email sent to Lab M on 8 January 2013:
I imagine that this isn’t a standard enquiry.
I’ve been mulling over an idea about trying to grow mould cultures into shapes through exposing bits of media through stencils for a while. I briefly and unsuccessfully tried this back in April using food grade agar as a medium: http://www.jamiedobson.com/pointlessendeavour/archives/1008.
I’ve done some research online this afternoon and discovered that this is probably more complicated but potentially much more interesting than I initially imagined.
This train of thought started back in 1997 with this:
Could you recommend some media and some catalysts with which to grow visible types of interesting mouldy stuff (ideally non-life threatening)?
Thanks for your help, Jamie
Email received from Lab M on 9 January 2013:
This is a really interesting idea. Admittedly, somewhat akin to ideas that we have toyed with in our own labs – sometimes accidentally, sometimes intentionally – see the attached picture where we tried to recreate the ‘M’ from our logo with bacteria in a Petri dish (this took a fair bit of practice – making the right dilution of bacteria so as not to get a solid ‘lawn’ of growth, and see individual colonies).
What you’re trying to achieve is entirely possible, with some refinement of the method you’re using and perhaps the choice of agar.
In terms of agar, there are a number of different media you could use and your choice depends on how colourful you want your artwork to be. Some moulds produce pigment naturally (e.g. Penicillium chrysogenum (green with white border) or Aspergillus niger (black with white border). Most media designed for growing moulds media will encourage pigment production and therefore you will see a stronger pigment than on a basal agar (like the food grade agar you used in your experiment. Some media are coloured, so with careful selection of species you can see coloured moulds on a coloured background (see links 2 & 3). To give you some perspective, have a look at the following links on our website – the links are for a selection of different product pages which carry images of the prepared media with mould cultures growing.
I had a look at both the links you provided, and from the information you’ve put on I can see where you can make some adjustments to get better results – I’ve made some suggestions below (I hope you don’t mind! – the suggestions aren’t intended to patronise, but I have assumed (perhaps wrongly) that you don’t have a big science/lab back ground as your studies were/are architecture and design).
The best way to prepare the agar in the absence of lab equipment would be to add room temperature water to the powder, leave it to soak for 10 minutes (to remove any lumps/clumps), then bring it to the boil on a hob, mixing (by swirling the pan/flask) regularly. Any product with agar content needs to be boiled to dissolve the agar fully in the water (the melting point of agar is quite high – around 80oC or so). Once you’ve done this, you can dispense the agar into plates. Boiling the agar will also provide a good (though not perfect) degree of sterilisation in a non-selective (without antibiotics) medium. What this means in practice is that the potential for contaminating bacterial growth to overgrow your mould cultures is reduced.
In terms of the agar you use, food grade is possibly too pure to encourage good growth with pigment production. Basic bacteriological grade agars (see http://www.labm.com/products/agar-no-2-bacteriological-general-purpose/ or http://www.labm.com/products/agar-no-1-bact–high-clarity/) which will do a fair job alone for what you need. You only need around 15g per litre of water to produce a solid agar, so it’s not much at all. Petri dishes are usually poured with a 18-25ml fill depending on method used to pour plates.
Using the whisk as you did was a good idea, but you, quite rightly, attributed the bubbles to the whisk. The swirling method I recommended above should ensure that your preparation is mixed but not bubbly. The formation of some bubbles is inevitable when preparing media by hand. An easy way to get rid of bubbles on the surface of a poured agar plate is to flame them with a Bunsen burner (which burns off the oxygen). You could recreate this by using a gas lighter (like the sort used at home for lighting barbecues / candles as opposed to a small cigarette lighter). You need to do this immediately after pouring the plate, before the agar begins to set.
The biggest thing to consider in all of this is that by culturing moulds you’re creating a biohazard. Microorganisms are classified in safety levels for laboratory purposes. Most are minimum category 2 meaning laboratory containment and handling procedures. Even schools are limited in what they can use in science levels (I think they can only culture probiotic/live yoghurts now as anything else is potentially too dangerous with a large group of pupils). Moulds are particularly hazardous as they form spores which can easily become airborne. Spores are also able to survive on surfaces for long periods of time.
What might be a good idea if you want to continue with the culturing of microorganisms is to see if you can attach to a university (with microbiology laboratories) who may be able to give some basic training in lab techniques and good laboratory practice and also where you can work – safe in the knowledge that you, your art subjects and others in the vicinity are safe from biohazard. They may also be able to help you with preparation of the agar. Realistically speaking, I think you need to be in a laboratory to SAFELY work on what you’re trying to achieve.
I do hope this gives you some assistance.
With best regards, Lisa