Optimization of culture conditions for mycoepoxydiene production by Phomopsis sp. Hant25

Abstract

Culture media and fermentation conditions for cultivation of an endophytic fungus Phomopsis sp. Hant25 were investigated in order to improve the yield of mycoepoxydiene, a novel fungal metabolite having potent cytotoxic activity against many cancer cell lines. Mycoepoxydiene accumulated in the culture broth during the stationary phase of fungal growth. Modified M1D medium was superior to malt Czapek, and Czapek yeast autolysate broths in supporting mycoepoxydiene production. Pellet growth was the morphological form that favored biosynthesis of mycoepoxydiene. This could be achieved by incubating the culture statically for 6 days before shaking at 120 rpm. Incorporation of a cellulose paper disc into the culture flask promoted fungal growth at the liquid surface, which accelerated mycoepoxydiene production and maximized the final yield to a level of 354 mg l⁻¹, though fungal attachment to the solid support was not required. Since the peak concentration of mycoepoxydiene in the culture broth was followed by a steeply declining phase, the harvest time had to be precisely determined for maximum product yield. Understanding the factor(s) involved in rapid degradation of mycoepoxydiene could lead to improved final yields.

Endophytes as in vitro production platforms of high value plant secondary metabolites

“…This strategy has been successfully applied to the endophytic strain of Phomopsis sp. using absorbent cotton gauze and cellulose paper for yield enhancement of mycoepoxydiene by 1 and 1.2 fold, respectively (Thammajaruk et al, 2011).…”

Toward a Cancer Drug of Fungal Origin

“…It has also been noted that minor variations in the growth conditions or in nutrient availability can strongly impact the quantity and diversity of fermentation products. 32,33 The deliberate elaboration of cultural parameters to augment the metabolic diversity of a strain has been called the OSMAC (one strain, many compounds) approach. [34][35][36] The advent of new technologies, high-throughput bioassays, and analytical methodologies provides the opportunity to create new and unnatural environmental and nutritional conditions that can change the metabolite production in an almost unlimited and unpredictable manner.…”

“…Another element critical for success in microbial natural product‐based discovery, which has received relatively little consideration, is the manipulation of nutritional and environmental factors promoting secondary metabolite biosynthesis. It has also been noted that minor variations in the growth conditions or in nutrient availability can strongly impact the quantity and diversity of fermentation products . The deliberate elaboration of cultural parameters to augment the metabolic diversity of a strain has been called the OSMAC (one strain, many compounds) approach .…”