Genetic Modification of the Marine-Isolated Yeast Aureobasidium melanogenum P16 for Efficient Pullulan Production from Inulin

Abstract

In this study, in order to directly and efficiently convert inulin into pullulan, the INU1 gene from Kluyveromyces maximum KM was integrated into the genomic DNA and actively expressed in the high pullulan producer Aureobasidium melanogenum P16 isolated from the mangrove ecosystem. After the ability to produce pullulan from inulin by different transformants was examined, it was found that the recombinant strain EI36, one of the transformants, produced 40.92 U/ml of inulinase activity while its wild-type strain P16 only yielded 7.57 U/ml of inulinase activity. Most (99.27 %) of the inulinase produced by the recombinant strain EI36 was secreted into the culture. During the 10-l fermentation, 70.57 ± 1.3 g/l of pullulan in the fermented medium was attained from inulin (138.0 g/l) within 108 h, high inulinase activity (42.03 U/ml) was produced within 60 h, the added inulin was actively hydrolyzed by the secreted inulinase, and most of the reducing sugars were used by the recombinant strain EI36. This confirmed that the genetically engineered yeast of A. melanogenum strain P16 was suitable for direct pullulan production from inulin.

Overexpression of an Inulinase Gene in an Oleaginous Yeast, <b><i>Aureobasidium melanogenum</i></b> P10, for Efficient Lipid Production from Inulin

“…So far, it has been found that inulinase genes from different sources have been overexpressed in Saccharomyces cerevisiae △gal80 strain, Saccharomyces sp. W0, Pichia pastoris, Yarrowia lipolytica ACA-DC 50109 and A. melanogenum P16 Ma et al, 2015]. This also confirmed that the expression of the INU1 gene could indeed enhance the biosynthesis and secretion of the extracellular inulinase in the transformant API41 used in this study (Fig.…”

“…So far, among the yeasts, S. cerevisiae, P. pastoris, Y. lipolytica, K. lactis, Hansenula polymorpha, Schizosaccharomyces pombe, and Arxula adeninivorans have been widely used for the expression of heterologous genes and the secretion of foreign proteins and enzymes [Çelik and Çal, 2012]. Our results revealed that A. melanogenum P16 and A. melanogenum P10, used in this study, can also be used for these activities [Ma et al, 2015].…”

“…The low inulinase activity produced by A. melanogenum strain P10 may be due to the presence of invertase as discussed above. However, A. melanogenum EI36 overexpressing the same inulinase gene produced 40.92 U/mL of inulinase activity, while its wild-type strain P16 only yielded 7.57 U/mL of inulinase activity [Ma et al, 2015].…”

Taxonomic Approach for Species Diversity of Yeasts and Yeasts-like Fungi through D1/D2 Region of Large Subunit Ribosomal DNA Sequences

“…Earlier study showed that several species in this study have been used for many bioindustry interests. For example, A. melanogenum isolated from the mangrove ecosystem able to produce biopolymer pullulan (Ma et al, 2015). The basidiomycetous yeast, P. hubeiensis has ability to produce mannosylerythritol lipids (MEL), the biosurfactant for cosmetic (Konishi et al, 2011).…”

Hydrocarbons, the advanced biofuels produced by different organisms, the evidence that alkanes in petroleum can be renewable

“…melanogenum P5, must be elucidated and genetic engineering of the yeast for improved biosynthesis of medium chain-length (C 10 -C 20 ) alkanes by elimination of the genes responsible for biosynthesis of long-chain fatty acids must be carried out. Because of the well-characterized genetics and highly developed genetic manipulation techniques in the yeast (Chi et al 2013;Ma et al 2015), the yeasts such as A. pullulans var. melanogenum are expected to produce higher yields of hydrocarbons with variable composition through the techniques for biosynthetic biology.…”