Is there a dummy guide to making Polylactic acid thermoplastic?

Is there a dummy guide to making Polylactic acid thermoplastic?

I'd like to try and make my own thermoplastic as Mr. Bowyer talks about in his Pop!Tech podcast. I'm far from being a chemist and was wondering if someone has a step-by-step guide to making thermoplastic.

It's funny, I was just discussing this with a friend of mine yesterday. Neither of us are chemists either, so we weren't certain how the process should work.

As far as I can tell, you ferment starch to get lactic acid, then polymerize that to get PLA.

We got as far as guessing that the bacteria in yogurt starter might ferment corn starch into lactic acid. For polymerization, it looked like heating it up with some sort of metal oxide catalyst (tin oxide was mention in some web articles) would do the trick.

Of course, this is all just wild guessing.

[www.vscht.cz]
followed by:
[www.fibtex.lodz.pl]

The first gives the names of the best bacteria for lactic acid production and talks about how to keep them happy and provides some preliminary (but high tech and optional) steps for increasing the concentration of the lactic acid solution. The solution must then be concentrated to a useful extent (90+%) by distillation at 85C under a hard vacuum (1 mm). The second paper discusses the creation of the actual polymer. Essentially, the lactic acid is mixed with 4 times as much of a solvent like ether and one tenth as much tin (all amounts are by weight) and cooked for 10 to 20 hours while the resulting h2o is captured. The whole thing is then added to 5 times as much wood alcohol and the precipitate is your polymer. The actual efficiency (grams polymer out/grams Lactic Acid in) of the process is not discussed.

Obviously, none of this is as simple as it sounds, some of it is really dangerous, and don't try this at home unless you understand these papers (and several others like them) throughly.

YMMV Void where prohibited. Author is not responsible. etc. etc.

So by the sounds of that I would go as far to say that this is not the home grown solution that Mr Bowyer makes it sound. I was hoping to find a much simple guide but it seems that the process is not all that simple. It is interesting tho!

This is not currently a homebrew process, but it is not hard to envision a set of machinery and procedures that would make it fairly straight forward. It is certainly no more dangerous than a lot of hobby pursuits. My point is that this is an area where the preliminary (Darwin level) work has not been done and that work will require people with particular skills if it is to go forward efficiently. I don't have those skills. I have internet access and a year of college chemistry, which is enough to know when I'm out of my league.

While I certainly support Adrian's vision of local, closed loop manufacturing economies, I do not think homebrew PLA is going to be a early step. PLA is a commodity item like capacitors or setscrews so there are going to be economic advantages to mass production of it until rising transportation costs or some other variable push economics considerably. Certainly remote, or impoverished areas or areas with excess agricultural capacity might want to create PLA plants of various capacities and I am sure they will find chemists to help them do it and I hope the results will be open sourced. If you are a practicing chemist with an anarchist bent, by all means set to work on a small, easy to operate PLA plant for the home or neighborhood. If you aren't a practicing chemist feel free to do so, but don't be surprised if you get jammed in a dead end and don't have your lawyer call me if you hurt yourself. :-)

On a guess, I would compare home PLA production today to home biodesiel production 20 years ago, when it was arcane, a little dangerous, and rare, but theoretically possible.
Today you can indeed buy a machine to keep in your garage which you need only feed the proper fluids in order to produce high quality fuel. There are also step-by-step guides to foolproof DIY biodesel in the kitchen. Is it economically feasible for the average city dweller? Farm dweller? Will it be if the price of petroleum triples? These are now the relevant questions.

Right now I see my part in all this as creating a machine so cool and powerful and easy to use that it starts to drive world production of PLA upwards. Then I'll worry about who makes the stuff.

Edited 1 time(s). Last edit at 12/17/2007 01:20PM by BDolge.

Sorry if I'm a little late to join in on the thread.
I just saw it recently and as a chemist just wanted to confirm what BDolge has said above.
Sadly PLA is not so easy to synthesize as would be desirable. Several of the steps above are cumbersome, some of them are even frankly dangerous. But it is possible to do, specially if done in a bigger operation. Will you m,anage to eat the price of imported PLA? I doubt it. Right now it's better to find a cheap source of wholesale PLA and distribute it smartly.

I always wondered if going the way of recycling Polyethylene or Polypropylene would not make more sense, economically and on ground of feasibility. But on the other hand I'm not a expert in thermoplastic extrusion and PE/PP extrusion might be several times more difficult than PLA's

BDolge Wrote:
-------------------------------------------------------
> [www.vscht.cz]

> The first gives the names of the best bacteria for
> lactic acid production and talks about how to keep
> them happy and provides some preliminary (but high
> tech and optional) steps for increasing the
> concentration of the lactic acid solution.

do you have the name of the document? URL is not valid anymore, and with a filename such as 5.pdf it will be hard to find it.. maybe you can find an up-to-date URL?

thanks

I am a graduate student in biochemistry and working a project to develop an open source PLA production procedure [opensourceecology.org]. If you are interested in finding a lactic acid bacteria for production there are a few considerations to take into account: productive efficiency, product specificity, and steriospecificity. I have a literature review in progress [opensourceecology.org] , sorry its still messy and I will be cleaning it up over the next couple months. Lactobacillus has been used commercially mainly because it was known to the food industry but it produces a mix of enantiomers, so industry goes the racemic lactide (two lactic acids formed into a ring) ring opening polymerization route which organizes the lactic monomers into an alternating pattern. Alternatively other bacterial strains (or genetic engineering routes) have been found create chirally pure L(+) that can be polymerized directly. I have yet to see literature on this route and is the one I am trying to take, though there are certain IP issues using these strains. Happy to discuss more if anyone is interested.

Speaking as a soon-to-be biochemistry grad student, how hard would it be to engineer an enzyme to polymerize lactic acid in vivo?

Check this out [www.ncbi.nlm.nih.gov]

It has been done using the PHA synthase (PhaC) after mutagenesis in E coli and seems to be a route worth investigating [onlinelibrary.wiley.com]. Lactic acid is an end product of a fermentation and higher concentrations inhibit the fermentation reaction. The work I have seen so far has all used intracellular expression of the enzymes which traps the (P)LA/PHA in the cell. I think a key step is to export the enzymes (the synthase uses a lactyl-CoA so a transferase and S-CoA are needed first I think) to the media so that cells are not inhibited and product can be collected without lysing and separating from cells. Also an efficient lactic acid producing bacteria would increase overall efficiency, it can be done in E coli with a lot of tinkering but we know a lot about how to do that in E coli, versus using a LA bacteria that is already good at producing high titers of LA but which the techniques for metabolic engineering haven't been worked on as much. Would definitely be a cool thesis project, especially with incorporated cellulases too. Personally I don't see much advantage to working out the flux problems when a "simple" mechanical process can do it "better."

Poli
have you considered doing your work with acorns instead of corn? I ask because that is what led me to this thread. I am a hardware guy so this all went way above my head, but I can follow a recipe like a champ. I live in scrub oak country, its crazy how many acorns come off so small of a tree. dozens of 5 gal buckets a year just from the yard. I could harvest tons for pretty much my time. Right now they are just a nussiance.

Poli I have gone through your page [opensourceecology.org]. excellent work thanks best of luck with your project implementation later this year, fingers crossed.

We are pursuing similar goals here using cassava starch rather than corn starch. We are just starting to map out our first laboratory demo for stage 1 starch -> lactic acid.

I have a few questions about your process diagram.
0. In a lab would something like this do for the PVDF filter ?
[www.amazon.com]

1. What kind of affordable/commonly available filter would use for stage 1 & 2 nano filtration, would some sort of hepa filter do the trick ?

2. What is the acceptance criteria for polymerization grade latic acid ?

3. you discuss electrodialysis but it is unclear where this fits in the process. I assume this is after stage 1 nanofiltration ? Also I have no idea what you mean by an "electrodialisis stack of 3-8 cells" ? could you clarify where does electrodialysis fit in the process ? what are the inputs and outputs ?

disclaimer : sorry if these questions are very basic but we don't actually have anyone with more than high school level chemistry here.

Have you finished your review and what is the best way (lowest cost way) to produce Lactic acid and PLA?

Sorry I haven't checked this thread in a while. Disappointingly I haven't had time to work on the project this semester but still want to continue to develop it now by designing hardware necessary. Disclaimer: I am not an expert just a student and this is a side project but I would input from experts.

youngwt1: I consider the review to cover most of the pertinent areas but still needs some articles summarized and then to be formatted and edited. Based up the available published information I think the plan is solid at least based the premise that an alternative to petroleum should be developed. I will being finishing the review and attempting to design hardware to carry out the process.

yoda: Cassava sounds like an excellent feedstock, I would like to hear about any progress you make. PVDF membranes seem to be a good option for micro-filtration, those membranes work well for biolab personal experience but crossflow filtration will probably be necessary to avoid quick fouling. I think HEPA filters still have to large of a pore size of .3 um, the manufacturer I am looking at is Sepro but I don't know the price - probably pretty high. Simply, polymerization grade lactic acid means lactic acid which can be polymerized, this probably means 90%+ LA with good desiccation equipment, and no contamination which prevents polymerization. Before I read that nanofiltration can be used to remove salts and concentrate lactate to lactic acid I thought electrodialysis would be necessary. Hopefully it's not necessary. The input would the microfiltered lactic acid broth and the output would be pure (salt free LA+H2O) but dilute lactic acid. This product would be concentrated by evaporation for polymerization. Membranes work by separating two chambers with a semipermeable barrier with or without a driving force. Electrodialysis stacks include the pairs of membranes and all of the chambers (and fluidic equipment for operation), depending on the configuration this can be 1 bipolar membrane or a pair of charged membranes and therefore 2 or 3 chambers.I think combining stacks is more energy efficient use of the current.

Mitchell: Acorns very well could be an excellent feedstock.

It would be good to do experiments as proposed by Poli. We are taking applications from anyone qualified to collaborate on design and to run the required experimental procedures. We can consider a residency at OSE's facility to move this forward in 2015. If you are interested, please email me at marcin at opensourceecology dot org.

From this article: [3dprintingindustry.com]

There is apparently a way to produce lactic acid 17 times more cheaply. Hopefully it involves more simple steps... The paper is available here: [pubs.rsc.org]

i dont understand any of this stuff so i hope someone has access to the paper and can tell us what processes it involves.