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

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.

Complete Genome Sequence of the Type Strain Tepidimonas taiwanensis LMG 22826T, a Thermophilic Alkaline Protease and Polyhydroxyalkanoate Producer

“…The high number of genes in these two groups corresponded to housekeeping functions of cells but was also related to industrially utilizable features, for example, the ability to produce PHA. Its production by the strain T. taiwanensis LMG 22826 T was proved recently, and the presence of phaC gene was confirmed by PCR ( Kourilova et al 2021 ). Here, we identified loci of phaC (LCC91_05560) and neighboring phaR (LCC91_04215) genes that are necessary for PHA production as well as a locus of phaZ (LCC91_05500) coding PHA depolymerase.…”

“…Nevertheless, other important features of the strain remained hidden, which may be due to the missing high-quality complete genome assembly and functional annotation of the genome. Only recently was its ability to utilize glucose and fructose to produce PHA reported ( Kourilova et al 2021 ). As it is a thermophile, PHA production takes place within the temperature range 45–55 °C, which reduces the risk of microbial contamination.…”

Advances in Polyhydroxyalkanoate (PHA) Production, Volume 3

“…It turned out that the strain harbors a Class I PHA synthase similar to other well-known short-chain-length PHA ( scl -PHA) producers like C. necator . Best results for P(3HB) production by this strain were obtained using extract of pomace remaining from pressing Veltliner grapes; here, almost 5 g/L biomass, containing about 48 wt.% P(3HB), were achieved within 72 h of cultivation at a thermophilic cultivation temperature of 50 °C, which is far above the typically mesophilic temperature optimum of established PHA production strains and most potential microbial contaminants [ 12 ].…”

The Pathway Analysis of Tepidimonas taiwanensis LMG 22826T, Polyhydroxyalkanoate and Alkaline Protease Producer

“…The ability to produce PHA by T. tawanensis LMG 22826 T was already experimentally proved with the cultivation of bacterium on grape pomace extract with the highest use of glucose and fructose as sources of carbon [5]. A member of the PHA family, polyhydroxybutyrate (PHB) was found to be synthesized, precisely 3-hydroxybutyrate (3HB) [5] which has potential to be used in a wide range of applications from plastics to the medical industry.…”