Fermentative Production of Lasiodiplodan by Lasiodiplodia theobromae CCT3966 from Pretreated Sugarcane Straw

Abstract

Lasiodiplodan is a β-glucan polymer with different interesting characteristics, including therapeutic properties. It is an extracellular product, which is produced by the filamentous fungus Lasiodiplodia theobromae, using glucose as a substrate. In the present work, the production of lasiodiplodan was studied by the utilization of sugarcane straw as a low-cost carbon source. Glucose-rich sugarcane straw hydrolysate was obtained by a sequential pretreatment with dilute nitric acid (1% v/v) and sodium hydroxide (1% w/v), followed by enzymatic hydrolysis. The fermentation process was conducted by the cultivation of the strain Lasiodiplodia theobromae CCT3966 in sugarcane straw hydrolysate in a shake flask at 28 °C for 114 h. It was found that hydrolysate obtained after enzymatic hydrolysis contained 47.10 gL−1 of glucose. Fermentation experiments of lasiodiplodan synthesis showed that the peak yield and productivity of 0.054 gg−1 glucose consumed and 0.016 gL−1 h−1, respectively, were obtained at 72 h fermentation time. Fungal growth, glucose consumption, and lasiodiplodan production from sugarcane straw hydrolysate presented a similar pattern to kinetic models. The study on the chemical structure of lasiodiplodan produced showed it had a β-glucan construction. The current study revealed that sugarcane straw is a promising substrate for the production of lasiodiplodan.