BioChem - DOS

Improving mycelium-bound lipase production by aggregating Rhizopus chinensis on a draft tube in a modified stirred tank fermentor

Process biochemistry

Wang, D.; Zhu, Z.; Wang, X.; Bustamante, M.; Xu, Y.; Liu, Y.; Liao, W.

Rhizopus chinensis (CCTCC 2010021) is a filamentous fungus that demonstrates a good capability to produce mycelium-bound lipase (mb-RCL) for ester synthesis in non-aqueous solutions. It has been reported that the mycelial aggregation of the fungal growth promotes mb-RCL production compared to free cell growth. This study modified a stirred tank reactor (STR) to accommodate a perforated draft tube so that aggregated growth of the fungal mycelia in the reactor was achieved. The aggregated growth on the draft tube not only improves mb-RCL accumulation but also changes the broth's rheological properties. Computational fluid dynamic (CFD) modeling and flow pattern verification conclude that the preferred fermentation condition was agitation at 600rpm and aeration at 1vvm (4L/min). Under this condition, the aggregated R. chinensis in the modified STR can fully utilize olive oil to accumulate 19g/L fungal biomass. The mb-RCL activity reached 325U/g, which corresponds to a total enzyme activity of 6185U/L fermentation broth. It was 6.5 times greater than the total enzyme activity in free cell fermentation. These results indicate that controlling the flow pattern of the broth by changing the agitation and aeration in the modified fermentor are able to improve mixing and mass transfer and lead to a better fermentation performance.

2015

Elsevier Applied Science

1359-5113

50

12

pp.2019-2028

10.1016/j.procbio.2015.10.004

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART73791739

Rhizopus chinensis; Fungal morphology; Lipase; Synthetic activity; Fermentor; Computational fluidic dynamics (CFD)