Single-cell Protein and Xylitol Production by a Novel Yeast Strain Candida intermedia FL023 from Lignocellulosic Hydrolysates and Xylose

Jiaqiang Wu,Xiangyang Ge,Mingxiong He,Nan Peng,Shumiao Zhao,Jinlong Hu,Guoquan Hu

doi:10.1007/s12010-017-2644-8

Abstract

Yeasts are good candidates to utilize the hydrolysates of lignocellulose, the most abundant bioresource, for bioproducts. This study aimed to evaluate the efficiencies of single-cell protein (SCP) and xylitol production by a novel yeast strain, Candida intermedia FL023, from lignocellulosic hydrolysates and xylose. This strain efficiently assimilated hexose, pentose, and cellubiose for cell mass production with the crude protein content of 484.2 g kg−1 dry cell mass. SCP was produced by strain FL023 using corncob hydrolysate and urea as the carbon and nitrogen sources with the dry cell mass productivity 0.86 g L−1 h−1 and the yield of 0.40 g g−1 sugar. SCP was also produced using NaOH-pretreated Miscanthus sinensis straw and corn steep liquor as the carbon and nitrogen sources through simultaneous saccharification and fermentation with the dry cell productivity of 0.23 g L−1 h−1 and yield of 0.17 g g−1 straw. C. intermedia FL023 was tolerant to 0.5 g L−1 furfural, acetic acid, and syringaldehyde in xylitol fermentation and produced 45.7 g L−1 xylitol from xylose with the productivity of 0.38 g L−1 h−1 and the yield of 0.57 g g−1 xylose. This study provides feasible methods for feed and food additive production from the abundant lignocellulosic bioresources.

Highlights

IntroductionThere is a growing interest in utilization of renewable bioresources for production of biochemicals (such as xylitol and lactic acid) and single-cell proteins (SCPs)
There is a growing interest in utilization of renewable bioresources for production of biochemicals and single-cell proteins (SCPs)
Cellobiose, one of the main factors in feedback inhibition of cellulose hydrolysis, was quickly assimilated by FL023 (Fig. 1). All these results suggested the strain FL023 has great potential in singlecell protein (SCP) production using the lignocellulose as the carbon source

Summary

Introduction

There is a growing interest in utilization of renewable bioresources for production of biochemicals (such as xylitol and lactic acid) and single-cell proteins (SCPs). Renewable bioresource provides cost-effective feedstock as it is the most abundant source of sugars and does not compete with food resources [29]. Chaetomium cellulolyticum, a cellulolytic fungus, degrades lignocellulose via a secreted cellulase to produce SCP [10, 24, 25]. Aspergillus terreus degrades alkali-pretreated sugarcane bagasse to produce SCP; optimum conditions yield a protein content of 210–280 g kg−1 [7]. C. langeronii, and C. arborea have been used with sugar cane bagasse and rice straw hydrolysate to produce SCP [27, 30, 42]. Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis assimilate non-detoxified hemicellulosic hydrolysate from spent brewery grains; D. hansenii showed the best performance with a productivity of 0.56 g L−1 h−1 [6]

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Results

Conclusion