BioChem - DOS

Continuous citric acid production in repeated-fed batch fermentation by Aspergillus niger immobilized on a new porous foam

Journal of biotechnology

Yu, Bin; Zhang, Xin; Sun, Wenjun; Xi, Xun; Zhao, Nan; Huang, Zichun; Ying, Zhuojun; Liu, Li; Liu, Dong; Niu, Huanqing; Wu, Jinglan; Zhuang, Wei; Zhu, Chenjie; Chen, Yong; Ying, Hanjie

<P><B>Abstract</B></P> <P>The efficiency of current methods for industrial production of citric acid is limited. To achieve continuous citric acid production with enhanced yield and reduced cost, immobilized fermentation was employed in an <I>Aspergillus niger</I> 831 repeated fed-batch fermentation system. We developed a new type of material (PAF201), which was used as a carrier for the novel adsorption immobilization system. Hydrophobicity, pore size and concentration of carriers were researched in <I>A. niger</I> immobilization. The efficiency of the <I>A. niger</I> immobilization process was analyzed by scanning electron microscopy. Then eight-cycle repeated fed-batch cultures for citric acid production were carried out over 600 h, which showed stable production with maximum citric acid concentrations and productivity levels of 162.7 g/L and 2.26 g L<SUP>&minus;1</SUP> h<SUP>&minus;1</SUP>, respectively. Compared with some other literatures about citric acid yield, PAF201 immobilization system is 11.3% higher than previous results. These results indicated that use of the new adsorption immobilization system could greatly improve citric acid productivity in repeated fed-batch fermentation. Moreover, these results could provide a guideline for <I>A.niger</I> or other filamentous fungi immobilization in industry.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new type of porous foam was employed in an adsorption immobilization system. </LI> <LI> Morphological changes in the <I>A. niger</I> immobilization system were analyzed by SEM. </LI> <LI> The highest concentration of citric acid reached 162.7 g/L in immobilization. </LI> <LI> Citric acid productivity kept highly in repeated fed-batch cultures over 600 h. </LI> </UL> </P>

2018

Elsevier

0168-1656

1873-4863

276

pp.1-9

10.1016/j.jbiotec.2018.03.015

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART84884177

Aspergillus niger; Immobilized fermentation; Citric acid; Biofilm; PAF201