Wastewater sludge as a potential raw material for antagonistic fungus ( Trichoderma sp.): Role of pre-treatment and solids concentration

• Published in: Water research (Oxford) 2005-09, Vol.39 (15), p.3587-3596
• Main Authors: Verma, Mausam, Brar, Satinder K., Tyagi, R.D., Valéro, J.R., Surampalli, R.Y.
• Format: Article
• Language: English
• Subjects: alkalinity; Animals; Applied sciences; Bacillus thuringiensis; Biocontrol agent; Biodegradation, Environmental; Biological and medical sciences; biosolids; Biotechnology; Choristoneura fumiferana; Colony Count, Microbial; Conidia; Conservation of Natural Resources; Entomotoxicity; Environment and pollution; enzyme activity; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; fungal antagonists; Hot Temperature; Hydrogen-Ion Concentration; Hypocrea rufa; Industrial applications and implications. Economical aspects; Larva; Lepidoptera; microbial growth; microbial pesticides; Other industrial wastes. Sewage sludge; Peptide Hydrolases - metabolism; Pest Control, Biological; Pollution; Pre-treatment; proteinases; Sewage - adverse effects; Sewage - analysis; Sewage - microbiology; Solids; Trichoderma; Trichoderma - growth & development; Trichoderma - metabolism; Trichoderma - pathogenicity; Trichoderma viride; Waste Disposal, Fluid - methods; Wastes; Wastewater sludge; wastewater treatment; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2005.07.001

Feasibility of production of antagonistic Trichoderma sp. conidial spores using wastewater sludge as a raw material employing different suspended solids concentration (10–50 g/l) was investigated in shake flasks. Maximum conidial spore count obtained for raw sludge was 1.98×10 4 CFU/ml, which was enhanced by sludge pre-treatments (alkaline and thermal alkaline). Conidial spore count ranging from 1.3×10 6 to 2.8×10 7 CFU/ml was observed for alkaline and thermal alkaline treated sludges. Optimal suspended solids concentration was 30 g/l (10 7 CFU/ml) whereas, lower (30 g/l) solids concentration were less efficient. Thermal alkaline pre-treated sludge showed diauxic growth due to multiplicity of sludge biodegradability. A simple, modified CFU filtration technique was also developed for fungal spore assessment in sludge. Bioassay of fermented sludge against spruce budworm larvae showed entomotoxicity (15036 SBU/μl), on par with Bacillus thuringiensis biopesticides. This study successfully demonstrated potential of wastewater sludge as a raw material for production of value added product, aiding in sludge management and proliferation of eco-friendly and economical biocontrol agents.