Colloidal Chitin Protocol
With a little help from a couple of colleagues, I've think I've found a better way to make useful colloidal chitin for my media. The protocols I'd found left out an important step, so here's what I'm doing now:
- Add one part powdered chitin to ten parts concentrated HCl while stirring.
- Let stand for six hours while stirring continues.
- While stirring continues, add five parts 100% ethanol at 4°C for every part HCl (50 ml HCl requires 250 ml EtOH, etc.)
- pH the mixture to 6.0-6.5 using sodium acetate solution.
- Decant into appropriate centrifuge bottles and spin down at 8,000 rpm for 40 minutes.
- Check pH; remove supernatant and wash again with sodium acetate as necessary and re-centrifuge until desired pH remains consistent (it changes a bit as hydronium get released by oligomers).
- Remove precipitated colloidal chitin with a spatula.
- Place the colloid in a coffee filter and dry in a food dehydrator for as long as necessary.
Applying too much heat results in the useless "chitin boogers" I mentioned previously. A food dehydrator at low power seems ideal for this application. I'm finishing a small batch of colloidal chitin today. If all goes well and my product is as useful as it appears it's going to be, I'll mix up one or two big batches, slice the spun-down colloid into even slabs, dry it and have enough on hand for some time to come. Working with concentrated HCl is no fun at all and I'd like to get it over with.
And gee, don't I just feel like Mr. Wizard about now? I write this entry mainly for some hypothetical future researcher who will someday get on Google searching for a protocol for making this stuff. It could happen. In fact, I noticed a hit from India a couple of days back that appears as if someone had done just that. If you are that person, hello... I hope you find this helpful and please share the reason you have for looking for this recipe. I'd be very happy to hear from other chitin/chitinase researchers about what they're up to.
