Organic neem compounds inhibit soft-rot fungal growth and improve the strength of anthracite bricks bound with collagen and lignin for use in iron foundry cupolas.

AIMS To examine organic neem compounds for their effective growth inhibition of saprotrophic soft-rot fungi on anthracite bricks bound with collagen and lignin for use in iron foundry cupolas as an alternative fuel source. METHODS AND RESULTS Azadirachtin, crude neem oil (NO), and clarified neem oil extract (CNO) were combined with copper to inhibit the growth of the soft-rot fungus, Chaetomium globosum. A synergistic interaction was observed between CNO and a low dose of copper on nutrient media (two-factor anova with triplicate replication: P < 0·05). Interaction was confirmed on lab-scale collagen-lignin-anthracite briquettes by measuring their unconfined compressive (UC) strength. The effective collagen strength of the briquettes was enhanced by applying CNO to their surface prior to inoculation: the room temperature UC strength of the briquettes was 28 ± 4·6% greater when CNO (0·4 mg cm(-2) ) was surface-applied, and was 43 ± 3·0% greater when CNO plus copper (0·14 μg cm(-2) ) were surface-applied. CONCLUSION Surface application of CNO and copper synergistically prevents fungal growth on bindered anthracite briquettes and increases their room temperature strength. SIGNIFICANCE AND IMPACT OF THE STUDY This novel organic fungicidal treatment may increase the storage and performance of anthracite bricks in iron foundries, thereby saving 15-20% of the energy used in conventional coke production.