Production of fungal chitosan for wastewater treatment
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Journal Title
Journal ISSN
Volume Title
Kemian tekniikan korkeakoulu |
Master's thesis
Authors
Date
Department
Major/Subject
Mcode
CHEM3022
Language
en
Pages
77+9
Series
Abstract
Chitosan is a promising alternative material for synthetic polymer in the flocculation process of wastewater treatment due to its biocompatibility, biodegradability, non-toxicity and adsorption properties. Currently, chitosan is produced from crustacean sources which have several drawbacks that limit the application of chitosan in the wastewater treatment industry such as high production cost, dis-continuous supply, limited fishing industry areas, or seasonal variations. Since chitosan is one of the main components of the cell walls of fungi belonging to Zygomycetes, thus fungi are the promising alternative sources for chitosan production. In this study, Absidia coerulea, Rhizopus microsporus var oligosporus, and Mucor circinelloides were found to be potential fungal sources for chitosan production with the highest extractable chitosan yields of 0.96 ± 0.02 g/L, 0.58 ± 0.05 g/L, and 0.93 ± 0.09 g/L, respectively. The DDA of chitosans extracted from fungal sources estimated using FT-IR were higher than that of standard crustacean chitosans. The extractable chitosans from fungal sources were believed to be mixtures of chitosan, glucan, and inorganic compounds. The charge densities of the fungal chitosan solutions at pH 3.3 were around 2.7 meq/g. The molecular weights of fungal chitosans were estimated to be from 250 to 890 kDa using GPC/SEC. The viscosities of the fungal chitosan solutions ranged from 2.2 to 3.6 mPas without the addition of NaCl, and from 2.0 to 2.9 mPas with the addition of NaCl. Furthermore, the performances of fungal chitosans as flocculants were tested using the CST test. The results indicated that chitosans extracted from fungal sources could be used as flocculants in the wastewater treatment industry with greater efficiency than chitosan from crustacean sources. Thus, chitosan produced from fungal sources has high potential to be used as flocculants in the wastewater treatment and other water-intense industries.Description
Supervisor
Frey, AlexanderThesis advisor
Recktenwald, MichaelUsvalampi, Anne