Effects of Calcium on the Morphology of Rhizopus oryzae and L-lactic Acid Production

Abstract

The effects of exogenous calcium on fungal pellet morphology during preculture and L-lactic acid production were studied. The results showed that addition of exogenous calcium could induce pellet formation. The diameter of the pellet increased with increasing concentration of exogenous calcium, including CaCl 2 and CaCO 3 . The smaller pellet precultured with low concentration of soluble calcium (CaCl 2 ) was beneficial for L-lactic acid production because the pellet was dense and the large inner part of the pellet was inactive. By contrast, the larger pellet precultured with high concentration of insoluble calcium (CaCO 3 ), except 8.0 g/L CaCO 3 , was beneficial for L-lactic acid production. Supported by the CaCO 3 powder, the entire biomass layer was fully active, and the highest L-lactic acid productivities of 1.22 g/L h and 58.6 g/L L-lactic acid were reached using the 1.5 mm pellet.

Asymmetric Bioconversion of Acetophenone in Nano-Sized Emulsion Using Rhizopus oryzae

“…Moreover, the removal of biomass after incubation will be easier when the pellet morphology is used [2,10]. Previous studies showed that the fungal pellet diameter was connected with the fermentation performance, and the highest yield was obtained when using pellets of smaller diameter, which may be interpreted that the inner zone of larger pellets was relatively inactive [4], limiting internal mass transfer [17]. On the other hand, the smaller pellet had an increased surface area, which can contact with more substrate.…”

Production of Edible Fungi from Potato Protein Liquor (PPL) in Airlift Bioreactor

“…The morphology is influenced by the strain characteristics as well as the medium composition and cultivation conditions [12][13][14][15]. Growth in pellet form has been reported as a favourable alternative for fungal cultivation, because it enables repeated-batch fermentation and improves the rheology of the broth, resulting in better mass and oxygen transfer in the reactor with lower energy consumption [12][13][14][15]. Morphology of the fungi can affect the production of primary and secondary metabolites [16].…”