Polymer recycling
Compositions and methods of making a culture medium from a polymeric material are described herein. The method can include (a) depolymerizing and/or dispersing the polymeric material to obtain a depolymerized and/or dispersed residue, and (b) combining the depolymerized and/or dispersed residue with one or more adjuvants to form a culture medium. In some embodiments, the polymeric material can be a plastic article, such as a waste carpet material. Culture media prepared from the compositions and methods are also described. The culture media are suitable for culturing microorganisms including bacterium, algae, and fungus. The microorganisms can be used to produce a bioproduct such as a biopolymer, an enzyme, or a cellular metabolite.
1. A method of making a microbial culture medium from a non-biodegradable polymeric plastic material, the method comprising:
(a) heating the non-biodegradable polymeric plastic material with a solvent to depolymerize and/or disperse the non-biodegradable polymeric plastic material and form a bioavailable polymeric mixture, wherein the solvent comprises an organic acid, an inorganic acid having a boiling point of 150° C. or less, a base, an oil, a non-polar organic solvent, or a combination thereof,
(b) processing the mixture comprising filtering, neutralizing, evaporating, distilling, rinsing, or a combination thereof to form a resin, and
(c) combining the resin with one or more adjuvants to form the microbial culture medium.
2. The method of claim 1 , further comprising the step of melting the non-biodegradable polymeric plastic material prior to step (a) heating the non-biodegradable polymeric plastic material with the solvent.
3. The method of claim 1 , wherein the non-biodegradable polymeric plastic material is derived from a carpet fiber.
4. The method of claim 1 , wherein the non-biodegradable polymeric plastic material comprises nylon.
5. The method of claim 1 , wherein the solvent comprises an organic acid, an inorganic acid having a boiling point of 150° C. or less, a base, or a combination thereof.
6. The method of claim 1 , wherein the solvent comprises an oil and the oil is selected from paraffin oil, olive oil, polyisobutene oil, hydrogenated polyisobutene oil, polydecene oil, polyisoprene oil, polyisopropene oil, fatty acids, vegetable oils, and combinations thereof.
7. The method of claim 6 , wherein the oil comprises a biodegradable surfactant.
8. The method of claim 1 , wherein in step (a), heating is from 50° C. to 300° C.
9. The method of claim 1 , wherein the one or more adjuvants are selected from water, acetate, lactose, glucose, fructose, maltose, ribose, a super optimal broth (SOB) media, a super optimal broth with catabolite repression (SOC) media, a nutrient broth, a nutrient agar, a minimal media, Luria-Bertani media, a sporulation broth, yeast extract, peptone, and combinations thereof.
10. The method of claim 1 , wherein depolymerizing the non-biodegradable polymeric plastic material is not carried out by enzymatic reaction.
11. The method of claim 1 , wherein the non-biodegradable polymeric plastic material has an average molecular weight of 10,000 D or greater.
12. The method of claim 1 , wherein step (a) comprises heating the non-biodegradable polymeric plastic material with an organic acid or an inorganic acid having a boiling point of 150° C. or less to depolymerize the non-biodegradable polymeric plastic material and form the bioavailable polymeric mixture.