Bálint, Balázs

English

Bálint Balázs

University of Szeged

Volume 50(3-4):137, 2006Acta Biologica Szegediensishttp://www.sci.u-szeged.hu/ABSDISSERTATION SUMMARYDepartment of Biotechnology, University of Szeged, Szeged, Hungary, and Institute of Biophysics, Biological Research Cen-ter, Hungarian Academy of Sciences, Szeged, HungaryBiohydrogen production from keratin-containing animal wastesBalázs BálintSupervisor: Kornél L. Kovács, Gábor RákhelyE-mail: balintb@brc.hu137Meat processing industry produces many kinds of kerati-nous waste materials (animal feather, wool, hair), which are degraded very slowly in nature, therefore, it is regarded as hazardous waste according EU directives. Decomposi-tion methods like incineration or chemical treatments are employed (Onifade et al. 1998), although these procedures are rather expensive or environment-polluting. In contrast, biotechnology offers environmentally sound and cheap or even economical biodegrading methods. Recently, a two stage fermentation system was constructed to convert keratin-con-taining biowaste into a useful product, biohydrogen (Balint et al. 2005). A keratin-degrading Bacillus strain was isolated and tested in waste decomposition experiments (Perei et al. 2000). During the biodegradation process keratin-containing material was converted into a fermentation product which was rich in amino acids and peptides. This mixture could be subsequently used as major nutrient source for an anaerobic hyperthermophilic achaeon, Thermococcus litoralis, which produced hydrogen gas as a physiological byproduct. The conceptual setup of the two-stage fermentation systemSeveral keratinaceous wastes (chicken feather meal, goose feather meal, pig hair) were digested by Bacillus lichenifor-mis KK1 and the fermentation product - supplemented with essential minerals - was subsequently used as nutrient for T. litoralis. Cell propagation, nutrient uptake and biohydrogen production were followed. The archaeon was found to utilize all three fermentation broths for biohydrogen production similarly to bacto-peptone, the standard peptidic growth substrate for T. litoralis in medium 623 (DSMZ). Besides T. litoralis two microbes (the gram negative E coli and the gram positive Caldicellusiruptor saccharolyticus) capable to produce hydrogen were examined but neither of them could utilize the keratin hydrolysate for biohydrogen production.Optimization of the keratin-degradation stepFeather meal degradation was subsequently optimised for the hydrogen production step and the optimal feather diges-tion time was investigated in few pH controlled experiments performed in a 700 ml batch fermenter. Protein concentra-tion of the cell-free fermentation broth was followed during fermentation and was found to increase significantly; 64% of the applied feather meal was solubilised within 60 hours. The picture of the samples taken from the fermenter and analysed on polyacrylamide gel confirmed that the feather materials were converted into small-sized soluble peptide fragments. Scale-up of the hydrogen producing stepHydrogen production studies were performed in a 7 l fer-menter at 85°C, pH=6,5, under nitrogen. Cell growth, con-sumption of alkali (used to maintain pH), nutrient uptake and biohydrogen production was monitored. All the followed parameters indicated substantial metabolic activity of the hydrogen producing cells in the first 30 hours of fermenta-tion. During this period 50% of the available peptides in the fermentation broth was utilized. Hydrogen production yield was found significantly higher than the earlier yields of small-volume pilot experiments. ConclusionWork presented here demonstrates the feasibility of biohy-drogen generation from keratin-rich biowaste. Using the de-veloped two-stage fermentation system it is possible to utilize animal feather, wool, hair and other protein-rich biowastes for biological hydrogen production. ReferencesBálint B, Bagi Z, Tóth A, Rákhely G, Perei K, Kovács KL (2005) Utilization of keratin-containing biowaste to produce biohydrogen. Appl Microbiol Biotechnol 69(4):404-410.Onifade AA, Al-Sane NA, Al-Musallam AA, Al-Zarban S (1998) A review: potentials for biotechnological applications of keratin-degrading micro-organisms and their enzymes for nutritional improvement of feathers and other keratins as livestock feed resources. Bioresour Technol 66:1-11.Perei K, Kovacs KL, Takacs J, Bagi Z (2000) Method of decomposing keratin by microorganisms, biomass obtained by the method, keratin-decompos-ing bacterium and its extracellular protease. Patent No.: 224974.

Biohydrogen production from keratin-containing animal wastes

http://acta.bibl.u-szeged.hu/22785/1/50137.pdf

Biohydrogen production from keratin-containing animal wastes

Abstract

Similar works

Full text

Available Versions

University of Szeged