Blue biotechnologies can contribute to exploiting marine biological resources to address key environmental problems in producing novel eco-compatible bioplastics. Microbial polyhydroxyalkanoates (PHAs) are biopolymers that have gained increasing biotechnological interest as alternatives to petrochemical plastics. However, PHAs industrial production is until now limited by high costs in the large-scale process. Crude glycerol, as a by-product of the biodiesel industry, represents an inexpensive carbon source for the production of value-added bioproducts. In this work, twenty bacterial Vibrio spp. strains, isolated from sediments collected from the Straits of Messina, were screened for their ability to accumulate PHAs granules in a mineral medium containing 2% of sodium chloride and added with glucose, sucrose and crude glycerol, as only carbon source. As evaluated by fluorescence microscopy, ten isolates grown with sucrose produced PHAs, whereas strain M3 was able to accumulate granules of PHAs using both sucrose or crude glycerol as sole carbon sources. An inexpensive fermentative process was designed using crude glycerol (3% v/v) to enhance the PHAs production and results at different incubation times were compared. Interestingly, the production of PHAs granules by strain M3 started after 12 h of incubation at 25°C and progressively increased until 24 h. The number of PHAs-producing cells increased after 24h (about 38%). In the examined growth conditions, PHAs from strain M3 represented about 22% of dried biomass. Strain M3 could be considered a candidate for commercial PHAs production using crude glycerol as the inexpensive feedstock. Future studies will be carried out to improve all the decisive factors in terms of costs such as raw materials and downstream processes, the physico-chemical properties and applications of PHAs in different applications in different industries, including food packaging, medical devices and drug carriers.

Polyhydroxyalkanoates produced by a novel marine Vibrio sp. strain from crude glycerol as carbon source

Zammuto V.;Rizzo M. G.;Spanò A.;Nicolò M.;Guglielmino S.;Gugliandolo C.
2021-01-01

Abstract

Blue biotechnologies can contribute to exploiting marine biological resources to address key environmental problems in producing novel eco-compatible bioplastics. Microbial polyhydroxyalkanoates (PHAs) are biopolymers that have gained increasing biotechnological interest as alternatives to petrochemical plastics. However, PHAs industrial production is until now limited by high costs in the large-scale process. Crude glycerol, as a by-product of the biodiesel industry, represents an inexpensive carbon source for the production of value-added bioproducts. In this work, twenty bacterial Vibrio spp. strains, isolated from sediments collected from the Straits of Messina, were screened for their ability to accumulate PHAs granules in a mineral medium containing 2% of sodium chloride and added with glucose, sucrose and crude glycerol, as only carbon source. As evaluated by fluorescence microscopy, ten isolates grown with sucrose produced PHAs, whereas strain M3 was able to accumulate granules of PHAs using both sucrose or crude glycerol as sole carbon sources. An inexpensive fermentative process was designed using crude glycerol (3% v/v) to enhance the PHAs production and results at different incubation times were compared. Interestingly, the production of PHAs granules by strain M3 started after 12 h of incubation at 25°C and progressively increased until 24 h. The number of PHAs-producing cells increased after 24h (about 38%). In the examined growth conditions, PHAs from strain M3 represented about 22% of dried biomass. Strain M3 could be considered a candidate for commercial PHAs production using crude glycerol as the inexpensive feedstock. Future studies will be carried out to improve all the decisive factors in terms of costs such as raw materials and downstream processes, the physico-chemical properties and applications of PHAs in different applications in different industries, including food packaging, medical devices and drug carriers.
2021
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/3219549
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