This study clearly demonstrates the feasibility of using less
expensive crude glycerol to grow R. arrhizus and produce fumaric
acid. It was found that crude glycerol was more suitable than glucose
for R. arrhizus forming smaller pellet. By the co-fermentation
of crude glycerol and glucose, fumaric acid production (22.81 g/L)
and glycerol consumption were both significantly enhanced, and
the production cost of fumaric acid was reduced by approximately
14% compared to glucose fermentation. Therefore, the co-fermentation
strategy proposes a cost-effective way for fumaric acid production,
while helping to solve the problem of waste glycerol
disposal.