Hey /sci/ anyone in here in the bioplastics industry? Or at

>>7730571
No but I'm a chemical engineer. I can do a back of the envelope calc for you if I can find a general synthesis path from some commonly available sugar to polylactic acid.

>brb googling

>>7730658
well I found this
http://www.academia.edu/4705232/Cost_Benefit_Analysis_of_Bioplastic_Production_in_Thailand

but idk I don't want to sign up or is academia.edu not bullshit?

also this
http://www.ourhealthyfuture.org/sites/default/files/pdfs/the_business_case_for_commercial_production_of_bioplastics_in_maine_final.pdf
reading through it not quite at the relevant bits yet.

AFAIK first step is just lactic acid fermentation, which would be almost free. But then there's the purification to polymer grade lactic acid, conversion to lactide, and then polymerization of the lactide monomers, I have no idea how any of these would go.

Found this though http://www.gizmag.com/bioplastic-pla-cheaper-production-process/38498/

I basically have access to a lot of inedible sugar.

>>7730672
also wondering how high the yield of lactic acid would be from natural fermentation, problem being the bacteria just keep on fermenting until they die. I'm wondering if there's a way to extract or at least separate cheaply the sugars to keep the fermentation going until the bacteria just run out of sugars.

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>>7730672
well shit Maine lolconfidential link had estimates on page 17

sorry for the thread...

>>7730658
>>7730571
So, the basics (you probably already know) using cheap starches (corn) to D-sucrose. Then D-Sucrose into lactic acid via fermentation. whether or not that is a more or less cost effective option than purchasing feedstock lactic acid would be determined by
>amount of PLA you want to make (tonnage / year)
>price variations in both feedstocks (cheap start vs lactic acid feed stock)


1) From there, it looks like there's a necessity for a high purity stereo-selective feedstock of low molecular weight lactic acid polymers. it looks like stereo selectivity and using starter molecules is pretty important. This will drive up purification costs considerably when using a cheap starch source. The separations involved are more than likely going to be capital investment low, but the high reflux in distillation columns will rape you in utilities. You will also have reactor capital costs as well as utilities for heating it for the initial formation of low MW starter molecules

That being said, Lactic acid production form these sources is very old and has been done for a long time and thus relatively "perfected". This might lead to purchasing clean Lactic acid as a feedstock being the better option (if you can find chemical price indexing for feedstock lactic acid, you'll be lucky. that shits hard to come by realistically if you're talking industrial scale, other wise there's ali baba .com for small orders)

2) after you have a clean feedstock of low MW Lactic acid polymers, the reaction that will take the most time. This occurs via catalytic dehydration of the starter molecules into linear chains. So
>capital costs for reactor (considerable, as you'll need a tin based catalyst, which is lucky its not an exotic metal)
>distillation costs to remove water to drive reaction equilibrium to the final products, also very energy intensive

The bad: it sounds like the bugs are proprietary, and economies of scale is the only thing that makes this really viable at all

>>7730685
>>7730675
>>7730672

Interesting they already had costs put out. The one thing to consider though, that is industrial scale production, in a chemical plant, with proprietary bugs, an R&D team behind them, and economies of scale behind them.

http://polymerinnovationblog.com/from-corn-to-polylactic-acid-part-2-making-the-pla-polymer/

was a much more synthesis friendly source.

as for
>yield of lactic acid
thats not really a huge issue in modern fermentation operations. If you can separate on the fly without hurting the bugs or their digestion kinetics, then you run a steady state fermentation and purge off the product.

if its not, then you up size batch scale operation so a single run gives you the timely throughput your looking for and discard the bugs.

>tl;dr, when conversion or yield is low, you just upsize the reactor within reasonable limits, which in this case wouldn't be that bad

>>7730685
no sorry needed. I enjoy this stuff very much, and its a pretty interesting quick mental run through for me.

>>7730697
D-Sucrose? I thought the go-to starter sugar was glucose? The sugar I basically have is just glucose + fructose.

Really sucks that stereo selectivity matters, does this mean I can't just grow any random lactic acid bacteria? Or will whatever strain dominates the culture prefer one stereoisomer over the other?

For the purification, is it just distillation? Lactic acid evaporates? Ah if so that would explain the smell lol.

Re: scale I'm looking at a couple million lbs a year of this inedible sugar.

>>7730675
whoops meant extract the acid

which appears to be feasible via distillation... If only I had a geothermal heat source at the same place this sugar is produced... Hmm maybe one of those solar setups with the converging mirrors.

>>7730712
if you check out the link >>7730707 they were talking about using dextrose (D-glucose)

Maybe it was just a yield thing, i didn't read to in depth, but i'm pretty sure you'd be able to get the fermentation going just fine using any other sugar.

As for the stereoselectivity, the big deal (as stated) were impurities during the initial heat driven dehydration (first reaction). thats where you could easily end up with the wrong handed molecules, which would fuck up the chains later during the second reaction IIRC. so yea, stereo selectivity at the time of fermentation is important.

As for getting the acid out, yeah there would be Distillation after the fermentation, but how many columns you need all depends on how many by-products there are wth your specific sugars and the bugs you use. On top of that though, the purification will probably have to happen. there will be alot of "garbage" in it, even if you run your towers with high reflux rations trying to get good separations.

>again, this is all just from what it sounds and there's a few companies with patents on the bugs and the purification process i think

>>7730721
well, odds are those wouldn't be hot enough. most distillation columns in indusry are run by 10-100 PSI steam (hotter than regular steam), as the reboilers need higher temps. for this situation, i rough estimate would be lactic acid and water

BP h2o - 100
BP lactic acid - 129

not alot of room to work there. it doesnmt appear they form an azeo trope though, the separation isnt going to be spectacular.

>>7730745
meant to add

*stereoselectivity is important, which probably is why they use D-glucose, and a proprietary bug

>>7730745
I don't mind the upfront time & cost of developing the bug, I have a bioengineering degree (haven't used it since I graduated 5 years ago hence why my brain is thirsty and I sound retarded) and access to a lab with PCR and idk how relevant these will be but a GC/MS, UHPLC, and a lot of basic lab equipment.

Hopefully these patents are just genomes and not vague hurrdurr any bacteria only capable of producing 95% optically pure lactic acid.

Some backend details that I probably shouldn't reveal involving production of said waste sugar makes the bioplastics option look less and less attractive. The insanely low oil prices aren't helping the case either. I just fell in love with the concept of bioplastics in general, so green and energy efficient. Maybe when the market matures the demand will grow and price will go up.

>>7730777
cool. its a neat pet project idea. at least worth working on a cloud diagram for it. but i'm off to bed. good luck friend