Waste Processing (Styrofoam)

During my time raising crickets and superworms I have noticed that styrofoam seems to be a poor choice for enclosure structure due to the insects tendency to consume it. I realize that this isn't really a "Bug Farming" question but I suppose raising insects to consume waste is still insect farming,

I would imagine in order to produce any sort of fertilizer; not too mention to keep your stock alive, that you would have to provide some kind of nutrition with the styrofoam. Due to styrofoams ability to absorb liquid I would wonder if you could bathe styrofoam in liquid waste and have it be consumed by insects.

I believe styrofoam is one of the few materials that we cannot recycle and having processing facilities that turn it into fertilizer I think would be an amazing advantage in our growing society. I would like to ask if anyone has tried anything similar otherwise I will likely commence some testing and report any findings here.


  • I have fed my mealworms styrofoam as a supplement to their normal diet of wheat bran, potato and carrots. They never consumed it all, so I had to filter it out...and they ate tunnels into them and burrowed in, so I literally had to touch every piece to pull out any hidden mealworms.

    I don't recall if it is possible for mealworms to survive on Styrofoam alone, I think I found info on this site by searching here or online to get some info.

  • http://cen.acs.org/articles/93/web/2015/09/Mealworms-Munch-Polystyrene-Foam.html

    This is an article on a study they did at a university in Beijing on Mealworms ability to process Polystyrene, apparently just using the mealworms results in unprocessed fragments being excreted in the waste of the mealworms. They are working on developing a bacterial culture that will process the remaining Polystyrene likely formed from the bacteria that processes it in the mealworms gut.

  • One of the comments I saw on the website Critters posted made a good point - polystyrene is technically completely reusable, where it's a "cradle to cradle" product the same way that we give mealworms waste plant material (bran) and turn it into valuable frass. However, I've read the papers at length and the polystyrene IS broken down in their waste. When administered the antibiotic, the polystyrene was no longer broken down, which is what confirmed the role of the bacteria in their gut. The main thing to figure out now is whether or not it would be valuable to incorporate polystyrene in their diets.

    I plan on setting up this experiment in the next months: Control group: 100% normal bran feed A: 10% foam by feed volume B: 20% C: 30%

    Considering the meager incorporation of carbon from foam into the mealworm's body, I would have to hypothesize that the control group will have the highest rate of growth, as any expenditure of energy in the breakdown/consumption of foam with no nutritional return will be detrimental to any kind of weight gain.

  • Hi samglickstein, - Maybe what is happening when certain bug gut microbes process styrofoam is less about freed carbon incorporation into the host larvae & more about members of the microbial consortium sharing metabolites. Then the host larvae is getting short chain fatty acids (& probably some vitamins) from those microbes to run through their bodies for use driving metabolic processes.

    My impression is that most talk/reseach about bug diet/nutrition looks at components (amino acids/protein, lipid chain/fat, carbohydrate & measurables) without reference to the gut microbes' processing of what consumed. This shows up when one hears how insects should be utilized by society since they are exceptionally efficient at resource utilization.

  • To maximize the utilization of styrofoam add yeast extract for the reportedly gram "negative" bacteral consortium involved (probably species of Pseudomonas, Alcaligenes & Acinetobacter). As per (2017) Tang, Kuo & Liu's "The study of microbes degraded polystyrene"; free full pdf available on-line.

    You can make cheap yeast extract by macerating yeast in water, boiling for 30 minutes, letting cool & then centrifuging to seperate out the starch component. Yeast extract will have about 7% amino acid nitrogen, B vitamin & inositol (inositol discussed elsewhere in forum, although not in regards to microbes).

  • Again samglickstein, - In terms of microbial growth, on average figure bacteria are 12.5 % nitrogen, 55% protein (itself usually 50% carbon, 7% hydrogen, 23% oxygen, 16% nitrogen ), 23% nucleic acid, 7% lipids, 9% carbohydrate, 6% ash & overall 48% carbon in one form or another .

    In the context of bacterial mass (weight) the average bio-reactor breeding estimate is you ideally can get 50 grams of bacteria from 100 grams of carbon processed. A ratio of 100 grams carbon : 10 grams nitrogen : 1 gram phosphorus (makes nucleic acids, ATP, ADP, phospholipids) is a common bacterial feed basis.

    For actual elements of atoms in a biological compounds these involve carbon & hydrogen (abreviated here as "CH" for convenience); the following ratios are presented as a convenient scale of reference. Hence to be DNA a proportion of 1.15 CH atoms + 0.62 oxygen atoms + 0.39 nitrogen atoms + 0.10 phosphorus atoms are incorporated. Or, to be RNA a proportion of 1.23 CH atoms + 0.75 oxygen atoms + 0.38 nitrogen atoms + 0.11 phosphorus atoms are incorporated. In the case of phospho-lipids (crucial to life & distinct from neutral fat) a lot more CH atoms are in it than the previous examples, being 1.91 CH atoms + 0.23 oxygen atoms + 0.02 nitrogen atoms + 0.02 phosphorus atoms (which is a lot less than in DNA/RNA).

    Not all carbon is destined for bio-mass of new cellular mater. A portion of carbon contributes to energy used to drive reactions, like that involved in the synthesis of new cell material. Some of that energy is diverted to drive turnover reactions within the cell & maintain functional material in the cell within proper concentration.

    Then too, some carbon taken into the bacterial cells is used to make (synthesize) extra-cellular compounds. One kind of item are external exo-enzymes used to break down substrates (food) that otherwise can not pass through bacterial cell walls.

    Another kind of extra-cellular products bacteria make are poly-saccharides needed for aggregating with other bacteria & binding metal ions. When experimenting with how much styrofoam is metabolizable bear in mind excess metal ions in the larval feed formula can inhibit some gut microbes leading to their slower growth/sythesizing.

  • Hi @gringojay! re: sharing of metabolites, it could very well be possible, almost like coral's symbiotic relationship with algae, but the paper states that mealworms fed exclusively foam had negligible weight gain, which leads me to believe that it could potentially sustain the worms, but not be a viable medium for them to be grown in. This is why I'm curious to see if a small incorporation of foam in their diets would lead to a reduced or similar growth rate to normal bran-fed larvae.

    Interesting, I didn't know that yeast also contained inositol (which I learned about from your post on the matter re: carrots).

    I'm unsure if the papers go in detail to uncover what compounds the microbes produce, but I would have to imagine there's some kind of give & take speaking in evolutionary terms. Regardless, the 0.5% of carbon being taken up has the larvae (at least in the papers) living in homeostasis with its intake of foam exclusively, which is what spurned my interest in seeing if supplementing their diet with it would have a hindering effect on growth rates. Would the bacteria in their gut "prefer" to aid in the digestion of the bran, or would the foam supersede the bran as a "preferred" source of energy for the bacteria? I'm not sure how the process works out in an ultra detailed manner.

    Would there be a surplus of metal ions in a simple bran/carrot feed?

    Thanks for your input.

  • edited July 2017

    @gringojay, sort of a side note, but I wanted to ask if you've heard of Allen Carson Cohen? His work is mainly on insect diets, and I have a few of his papers. I don't think he touches upon this subject at all, but I have his book "Insect Diets" and I highly recommend it to anyone in the community that wants to know more on the subject. While it focuses on rearing insects as a whole, it's a treasure trove of information for all kinds of scientific literature on this incredibly niche subject (with huge potential). Just an FYI.

  • Hi samglickstein, - In answer to your question about metals: there is no reason I can see where metal ions that are in a food item (& not contaminants taken up) would be a problem for bug gut microbes. My alert is for those fabricating bug diets & elaborating a mineral supplement to include in their formulation to avoid working on the assumption that "more is better" when it comes to all minerals.

    So, bran/carrot feed does not pose a surplus metal ion challenge . By the way, for a commercial operation in rural region you might locate a reliable source of carrot green tops to process into a diet ingredient. My mealworms prefer carrot juice pulp ("pomace") over greens & uneaten dry green flakes clung so much when cuulled out larvae I no longer put green juice pulp in their bran. Carrot leaves have nice amount of protein (among other nutrients) that could be extracted & when moistened with a suitable carrier sprayed on bran, then that bran is surface dried to create an enriched diet.

    As for A.C. Cohen's work I have no real knowledge, other than his index.

  • @gringojay, thank you for your response! Fabricating diets isn't something I would necessarily explore for something like mealworms, but I think a "proprietary blend" insect feed market would naturally arise from this growing industry. I definitely agree with the over-supplementation point. As I'm sure you're aware, in (cellular) biology, most compounds become toxic after a certain concentration is reached.

    Is there a reason you use pulped carrots as opposed to pieces? I would imagine that a pulp or any kind of more wet material would increase the risk of mold or other fungal pathogens from encroaching. Although my initial operation will be urban (Baltimore, MD), I am certainly considering moving my more commercial operation to rural MD where I have connections and existing land (on a farm, no less) ready to be developed. Perhaps I will grow my own carrots! What would you suggest is the best method to extract? Simple juicing? What exactly is a carrier spray?

    Check out A.C. Cohen if you have time. I've taken his online course with the University of North Carolina which is one of the only consolidated sources of insect rearing information that I've been able to find.

  • Hi, - I use TinyFarm mesh grow bags for mealworm age mate larvae & never found them utilizing carrot pieces/slabs/shreds until had grown alot. Anyway I got tired of managing so called "moisture" items (carrot/potato/etc.) for the larvae; breeding beetles still get "moisture" item (radish my best trade off in managing ease).

    I recycled juice bar pulp for compost worms & had lots of different combinations of ingredients. I found that just plain carrot juice pulp (pomace) spread conservatavely across part if the bran, but not covering all surface (just as is best with compost worm batch feeding) was highly attractive to larvae once they were old enough.

    If your larvae are age-mates (say from eggs collected 1-2 weeks apart) you can place a little carrot pulp on their bran once you see larvae mobilizing & if it seems untouched the next day then pluck it off the bran. When a bit more time elapses repeat the pulp offering & if some interest is evident the next day there will be more growing age mates coming along ready for carrot pulp. Then you can supply more by crumbling it over the bran & rotate the bran sector where putting it to avoid stagnating local circulation; the uneaten pulp cellulose will dry out & not get fungal.

    My operation is not commercial scale, so I make myself carrot juice (which like) & feed larvae the pulp; carrot juice can be made in a blender (chop roots, add water, blend, strain, squeeze out pulp). In an urban location I think one might get free carrot pulp.

    Mealworm larvae did not consume juice pulp from greens as much, so stopped adding it to avoid difficulty of clearing dessicated greens off harvested larvae. When spoke of carrier spray was in relation to dispending what get from processing carrot tops (not the root juice extract). Since your scale is not commercial at this point I see no cost benefit from work involved or equipment dedication.

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