Location: Crops Pathology and Genetics ResearchTitle: Conversion of deproteinized cheese whey to lactobionic acid by an engineered Neurospora crassa
|POLTORAK, ADAM - University Of California, Davis
|ZHOU, XIN - University Of California, Davis
|XU, YONG - University Of California, Davis
|ZHILIANG, FAN - University Of California, Davis
Submitted to: Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2022
Publication Date: N/A
Interpretive Summary: Lignocellulosic biomass is a renewable, low-cost, and abundant source for the production of biofuels. Several fungal pathogens are capable of decomposing lignocellulosic materials to sugar, therefore, have the industrial potential for bioenergy production. Interestingly, the same suite of enzymes can be used to convert lactose to lactobionic acid. Lactobionic acid is a versatile, high-value chemical with numerous applications in the food, pharmaceutical, cosmetic, and chemical industries. The source of lactose could be either refined lactose or cheaper lactose sources such as sweet cheese, whey deproteinized cheese whey, or acid whey. We have been developing fungal mutants that are able to convert lactose to lactobionate (sugar acid), but cannot consume lactose.
Technical Abstract: Lactobionic acid (LBA) is a versatile, high-value, low-volume chemical with numerous applications in the food, pharmaceutical, cosmetic, and chemical industries. LBA can be produced by a cellobiose dehydrogenase (CDH)/laccase (Lac) bi-enzymatic system with the presence of a redox mediator. An engineered Neurospora crassa strain F5 was evaluated for in-situ LBA production. The strain F5 produced CDH and laccase simultaneously on the pretreated wheat straw with 0.3 uM of cycloheximide added as the laccase inducer. Deleting the six out of seven '-glucosidases genes in F5 substantially slowed the lactose utilization rate and led to a higher level CDH production. . The deproteinized cheese whey can be added directly to the shake flasks with the fungus present to achieve LBA production. About 37g/L LBA was produced from 45g/L lactose in 27 hours. The yield of LBA from consumed lactose was about 87%. The LBA productivity was about 1.37g/L/hour.