Extraction and characterization of eumelanin from black soldier fly (H. Illucens) pupal exuviae: Investigating a novel source for eumelanin
Hyytiäinen, Mitja (2023)
Hyytiäinen, Mitja
2023
Teknis-luonnontieteellinen DI-ohjelma - Master's Programme in Science and Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2023-11-16
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202310309234
https://urn.fi/URN:NBN:fi:tuni-202310309234
Tiivistelmä
Eumelanin is a naturally occurring dark pigment with a variety of interesting properties such as photoprotection, broadband absorption and ability to chelate various metals. Eumelanin is also present in human skin in varying amounts, thus resulting in a variety of skin tones present across the human race. Although eumelanin, along with other members of the melanin family, has been researched extensively from the late 1960’s it has seldom been extracted from natural sources in commercially viable quantities. Recently, Black Soldier Fly (Hermetia illucens) has been reared commercially for their protein and lipids, but recent studies demonstrate that they might also have relatively high eumelanin content which open new opportunities for side stream utilization. However, there are only few earlier studies on melanin extraction from Black Soldier Flies.
The objective of this study was to examine if melanin-containing pigment can be chemically extracted from Black Soldier Fly pupal exuviae. Exuviae are the remains of the pupal exoskeleton left behind after the emergence of the adult flies. The specific research questions were: (1) whether melanin can be extracted from Black Soldier Fly exuviae biomass using a relatively simple chemical methodology; (2) whether the extracted melanin can be analyzed using common spectroscopic methods; (3) how does the weight-to-volume ratio of biomass per aqueous base affect extraction yield; and (4) whether the polymeric structure of the extracted melanin can be estimated using pyrolysis-gas chromatogram-mass spectrometer.
As a result of four-step extraction process, melanin-containing pigment was obtained. Upon qualitative analysis, the pigment was characterized as eumelanin. Weight-to-volume ratio of biomass per aqueous base of 1:8 was identified to have the highest yield among all the tested ratios. Pyrolysis-gas chromatogram-mass spectrometer measurements did not provide any insight into the polymeric structure. However, proton nuclear magnetic resonance measurements showed limited signs of carboxylic acid substituents. This implies that, the extracted eumelanin seems to consist mostly of monomers of 3,4-dihydroxyindole along with its redox forms and their tautomers.
This research has demonstrated that eumelanin can be extracted from Black Soldier Fly pupal exuviae in significant quantities by employing a relatively straightforward chemical extraction process. Thus, Black Soldier Fly pupal exuviae presents itself as a viable source of naturally available eumelanin with a variety of potential applications in industries such as to medicine and bioelectronics. However, further research into the stability and exact chemical composition of the extracted eumelanin pigment is needed in order to gain a more in-depth understanding of the pigment’s suitability for different applications.
The objective of this study was to examine if melanin-containing pigment can be chemically extracted from Black Soldier Fly pupal exuviae. Exuviae are the remains of the pupal exoskeleton left behind after the emergence of the adult flies. The specific research questions were: (1) whether melanin can be extracted from Black Soldier Fly exuviae biomass using a relatively simple chemical methodology; (2) whether the extracted melanin can be analyzed using common spectroscopic methods; (3) how does the weight-to-volume ratio of biomass per aqueous base affect extraction yield; and (4) whether the polymeric structure of the extracted melanin can be estimated using pyrolysis-gas chromatogram-mass spectrometer.
As a result of four-step extraction process, melanin-containing pigment was obtained. Upon qualitative analysis, the pigment was characterized as eumelanin. Weight-to-volume ratio of biomass per aqueous base of 1:8 was identified to have the highest yield among all the tested ratios. Pyrolysis-gas chromatogram-mass spectrometer measurements did not provide any insight into the polymeric structure. However, proton nuclear magnetic resonance measurements showed limited signs of carboxylic acid substituents. This implies that, the extracted eumelanin seems to consist mostly of monomers of 3,4-dihydroxyindole along with its redox forms and their tautomers.
This research has demonstrated that eumelanin can be extracted from Black Soldier Fly pupal exuviae in significant quantities by employing a relatively straightforward chemical extraction process. Thus, Black Soldier Fly pupal exuviae presents itself as a viable source of naturally available eumelanin with a variety of potential applications in industries such as to medicine and bioelectronics. However, further research into the stability and exact chemical composition of the extracted eumelanin pigment is needed in order to gain a more in-depth understanding of the pigment’s suitability for different applications.