Optimization of liquid culture medium for commercial production ofColletotrichum truncatum

Abstract

A commercial type liquid culture medium for the production of Colletotrichum truncatum NRRL 13737, a pathogen of the weed hemp sesbania, was developed. The concentrations of culture ingredients: 20 g glucose 1−1, 2.5 g Tastone yeast extract 1−1, 7.5 g Pharmamedia 1−1 are optimum for batch cultures. Initial glucose concentration determined total dry weight which was largely composed of mycelia: Pharmamedia concentration influenced the yield and rate of spore production; Tastone 154 yeast extract apparently supplied a nutritional factor which also affected the yield and rate of spore production but to a lesser extent. Batch culture with the described media yielded 6.2×107 spores per ml in three days. Studies of spore recovery, drying and storage can now be conducted with a commercial type culture medium.

Fermentation Strategies for Improving the Fitness of a Bioherbicide

“…A summary of the steps leading to the development of a low-cost production medium based on conidia yield and efficacy is outlined in Figure 2. A complex medium for producing highly efficacious C. trullcatllln conidia was developed which yields 5 x 10 7 conidia/ml in 4 d (14).…”

Biological Control of the Weed Sesbania exaltata Using a Microsclerotia Formulation of the Bioherbicide <i>Colletotrichum truncatum</i>

“…Solid substrates such as membranes, vermiculite and rice hulls, as well as liquid culture have been used to produce C. truncatum conidia [17]. Furthermore, Silman and Nelsen [18] and Jackson and Schisler [19] studied optimization of liquid culture media producing C. truncatum conidia. Various factors such as additives, pH and temperature can affect germination and virulence of C. truncatum, as well as the addition of other bioherbicidal pathogens, such as C. gloeosporioides in order to control two weeds: hemp sesbania and sicklepod [Senna obtusifolia (L.) Barnaby] [20] [21].…”