Potential for the Large-Scale Production Of a Biocontrol Fungus In Raw and Composted Paper Mill Waste

Abstract

The growth and survival of a Trichoderma spp. (Td₂₂) antagonistic to Sclerotinia minor Jagger and Sclerotium cepivorum Berk was studied in raw wood fibre waste (WFW) of paper mill origin and in mature compost of this material. In nutrient-amended, sterilized WFW or WFW compost (both supplemented with 20% w/w millet seed), the biocontrol fungus reached densities in the order of 10¹⁰ colony forming units (cfu)/g after 14 days incubation. Lower population densities of Td₂₂ were achieved under non-sterile conditions in the compost:millet mix of between 10⁷−10⁹ cfu/g after 28 days, depending on pretreatment. Viable spore density of Td₂₂ in raw WFW amended with nutrients and 20% w/w millet seed reached approximately 10¹⁰ cells/g after 14 days incubation. This study indicates that cellulosic paper mill waste could provide an abundant low-cost growth medium for the large-scale culture of this or other biocontrol fungi.