title: Biodegradation kinetics of thin-stillage treatment by Aspergillus awamori and characterization of recovered chitosan.
abstract: An attempt has been made to provide solution for distillery wastewater using fungal pretreatment followed by an anaerobic process to achieve higher organic matter removal, which is a challenge at present with currently adopted technologies. Submerged growth kinetics of distillery wastewater supernatant by Aspergillus awamori was also evaluated. The proposed kinetic models using a logistic equation for fungal growth and the Leudeking-Piret equation for product formation were validated experimentally, and substrate consumption equation was derived using estimated kinetic coefficients. Up to 59.6 % chemical oxygen demand (COD) and 70 % total organic carbon (TOC) removals were observed in 96 h of fungal incubation. Maximum specific growth rate of fungi, coefficient of biomass yield on substrate and growth-associated product formation coefficient were estimated to be 0.07 ± 0.01 h(-1), 0.614 kg biomass/kg utilized COD and 0.215 kg CO2/kg utilized TOC, respectively. The chitosan recovery of 0.072-0.078 kg/kg of dry mycelium was obtained using dilute sulphuric acid extraction, showing high purity and characteristic chitosan properties according to FTIR and XRD analyses. After anaerobic treatment of the fungal pretreated effluent with COD concentration of 7.920 ± 0.120 kg COD/m(3) (organic loading rate of 3.28 kg COD/m(3) day), overall COD reduction of 91.07 % was achieved from distillery wastewater.
authors.affiliation: P. K. Sinha Centre for Bioenergy, ATDC, Indian Institute of Technology, Kharagpur, 721302, India.
authors.forename: S Ghosh
authors.initials: SG
authors.lastname: Ray
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology, Kharagpur, 721302, India. ghangrekar@civil.iitkgp.ernet.in.
authors.forename: M M
authors.initials: MM
authors.lastname: Ghangrekar
mesh_terms: D001230:Aspergillus / Q000254:growth & development / Q000378:metabolism*; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D001711:Biotransformation; D002244:Carbon / Q000032:analysis; D048271:Chitosan / Q000737:chemistry* / Q000302:isolation & purification*; D007220:Industrial Waste; D009930:Organic Chemicals / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D002244:Carbon; D048271:Chitosan; D007220:Industrial Waste; D009930:Organic Chemicals; D062065:Wastewater
keywords: Aspergillus awamori; Chitosan extraction; Distillery wastewater treatment; Fungal treatment; Kinetics of fungal degradation