Characterization of Inulin Hydrolyzing Enzyme(s) in Oleaginous Yeast Trichosporon cutaneum in Consolidated Bioprocessing of Microbial Lipid Fermentation

Appl Biochem Biotechnol (2015) 177:10831098 DOI 10.1007/s12010-015-1798-5

Juan Wang1 & Huizhan Zhang1 & Jie Bao1

Received: 22 May 2015 /Accepted: 2 August 2015 / Published online: 26 August 2015# Springer Science+Business Media New York 2015

Abstract Oleaginous yeast Trichosporon cutaneum CGMCC 2.1374 was found to utilize inulin directly for microbial lipid fermentation without a hydrolysis step. The potential inulinase-like enzyme(s) in T. cutaneum CGMCC 2.1374 were characterized and compared with other inulinase enzymes produced by varied yeast strains. The consolidated bioprocessing (CBP) for lipid accumulated using inulin was optimized with 4.79 g/L of lipid produced from 50 g/L inulin with the lipid content of 33.6 % in dry cells. The molecular weight of the enzyme was measured which was close to invertase in Saccharomyces cerevisiae. The study provided information for inulin hydrolyzing enzyme(s) in oleaginous yeasts, as well as a preliminary CBP process for lipid production from inulin feedstock.

Keywords Inulin hydrolyzing enzyme . Trichosporon cutaneum . Dry cell weight . Lipid production . Consolidated bioprocessing

Introduction

Microbial lipid has a similar composition with plant oil and is considered as an alternative feedstock for biodiesel production [1]. Typical oleaginous bacteria, fungi, yeasts, and algae produce over 30 % (w/w) intracellular lipid of their cell mass [2]. Among these microbes, oleaginous yeasts such as Yarrowia lipolytica, Rhodosporidium toruloides, Lipomyces starkeyi, Trichosporon fermentans, Rhodotorula mucilaginosa, Trichosporon capitatum,

* Huizhan Zhang [email protected]

* Jie Bao [email protected]

1 State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology,

Shanghai 200237, China

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1084 Appl Biochem Biotechnol (2015) 177:10831098

Apiotrichum curvatum, Candida curvata, and Cryptococcus curvatus are advantageous for their fast growth rate, high oil content, and the resemblance of their triacylglycerol fraction to plant oil [3, 4]. When polysaccharides such as starch and lignocellulose are used as feedstock, a hydrolysis step is required to convert polysaccharides into monosaccharides for lipid fermentation. Recently, a consolidated bioprocessing (CBP) concept is proposed by combining hydrolyzing enzyme production, hydrolysis, and fermentation in a...