Biotechnological Conversion of Grape Pomace to Poly(3-hydroxybutyrate) by Moderately Thermophilic Bacterium Tepidimonas taiwanensis.

Xenie Kourilova,Kamila Hrubanova,Roman Krejcirik,Iva Pernicova,Katerina Mrazova,Stanislav Obruca,Vladislav Krzyzanek,Michaela Vidlakova,Jana Nebesarova

doi:10.3390/bioengineering8100141

Abstract

Polyhydroxyalkanoates (PHA) are microbial polyesters that have recently come to the forefront of interest due to their biodegradability and production from renewable sources. A potential increase in competitiveness of PHA production process comes with a combination of the use of thermophilic bacteria with the mutual use of waste substrates. In this work, the thermophilic bacterium Tepidimonas taiwanensis LMG 22826 was identified as a promising PHA producer. The ability to produce PHA in T. taiwanensis was studied both on genotype and phenotype levels. The gene encoding the Class I PHA synthase, a crucial enzyme in PHA synthesis, was detected both by genome database search and by PCR. The microbial culture of T. taiwanensis was capable of efficient utilization of glucose and fructose. When cultivated on glucose as the only carbon source at 50 °C, the PHA titers reached up to 3.55 g/L, and PHA content in cell dry mass was 65%. The preference of fructose and glucose opens the possibility to employ T. taiwanensis for PHA production on various food wastes rich in these abundant sugars. In this work, PHA production on grape pomace extracts was successfully tested.

Highlights

Pollution of the environment by solid resistant petrochemical polymers represents one of the most important ecological problems
The thermophilic bacterium Tepidimonas taiwanensis LMG 22826 can be a suitable candidate for PHA production [37]
Our basic bioinformatics analysis demonstrated that T. taiwanensis LMG 22826 harbors enzyme machinery necessary for PHA synthesis; it was found that the bacterium contains the gene encoding for the

Summary

Introduction

Pollution of the environment by solid resistant petrochemical polymers represents one of the most important ecological problems. Several million tons of plastic are produced, which has a wide range of uses, but a large part of them end up being thrown away and accumulating in nature. A potential solution of this problem might be, at least in part, the substitution of petrochemical polymers with biodegradable and renewable materials. One of the alternatives is polyhydroxyalkanoates (PHA). PHA are microbial polyesters that are produced by numerous prokaryotes in the form of intracellular granules to store energy and carbon, but in addition, PHA reveal a protective function concerning the adverse effects of the environment [1]. PHA can be divided based on chain length into scl-PHA (short-chain length), which contains three to five carbons in the monomer, and mcl-PHA (medium-chain length), which contains 6 to 14 carbons in the monomer

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Results

Conclusion