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A study on biochemical changes during cultivation of R hizopus oryzae in deproteinized whey medium in relation to chitosan production
Author(s) -
Chatterjee S.,
Guha A.K.
Publication year - 2014
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12259
Subject(s) - rhizopus oryzae , chitosan , food science , chemistry , sugar , lactose , bran , aspergillus oryzae , biochemistry , fermentation , raw material , organic chemistry
The kinetics of cultivation of zygomycete filamentous fungus R hizopus oryzae in deproteinized whey medium in relation to chitosan production was studied here to optimize chitosan production from R. oryzae as well as utilize whey, a by‐product of sweetmeat industry as a cheap source of sugar in the cultivation process. Chitosan content of R. oryzae biomass was found to be increased with time during cultivation and reached maximum (13·6%) after 72 h and then declined steadily. Maximum 1·13 g of chitosan was obtained from one litre of deproteinized whey medium. Concentration of lactose in the medium was observed to be reduced from 45·0 to 11·7 g l −1 during cultivation resulting in decrease in biochemical oxygen demand (BOD) of whey by approx. 60%, and this was important from environmental point of view before discharging whey into any water body. However, no significant change in pH or titratable acidity was noted during the entire course of cultivation, probably due to good buffering capacity of the medium. Molecular weight of chitosan varied from 130 to 230 kDa depending on the time of cultivation, but no significant change in degree of deacetylation of chitosan (approx. 87%) was found during cultivation. Significance and Impact of the Study Whey is the largest by‐product of dairy industries, and its disposal is a big environmental issue because of its high biological oxygen demand (BOD) value. This study will help to lower BOD value of whey by using it as a cultivation medium for fungus R. oryzae that contains chitosan, a very commercially important material on its cell wall. Moreover, the study on biochemical changes in whey during cultivation process with R. oryzae will help to understand the exact changes occurring in the medium and optimize cultivation process to isolate chitosan in larger extent with better and uniform physicochemical properties.