| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1265-2 | ||||
Resumo:Chitin and chitosan are copolymers consisting of units N-acetil-D-glucosamine and D-glucosamine in varying proportions, with the first type of these units is predominant in the chitin, while chitosan is composed predominantly of D-glucosamine units. Chitin is present as structural element in the exoskeleton of crustaceans and fungal cell walls, particularly of Zygomycetes. Chitin and chitosan have been extensively studied as due to unique properties such
biodegradability, biocompatibility, biological activities. The chitosan is obtained by the deacetylation of chitin. The biowaste from some industrial by-products such as corn steep liquor (CSL) and pineapple peel juice (PPJ) can be used as very economical nutritional sources of carbon and nitrogen for the production of these fungal polymers. These alternative favors obtaining a byproduct with high added value as well as decreasing total production costs. In this way, the present study aims to evaluate the use of CSL and PPJ as nutrition source for chitin and chitosan production by Rhizopus arrhizus. CSL was obtained from Ingredion Brazil Ltda. (Cabo de São Agostinho-PE, Brazil); fresh pineapple peel from fruit in 4th − 5th maturation stage was obtained from a local fruit processing industry (Garanhuns-PE, Brazil). R. arrhizus was inoculated in alternative medium with CSL and PPJ, according to a 22 central composite rotated design (CCRD 22), pH 5.6, 28 °C, 150 rpm, for 96 h. A CCRD 22 design was carried out to analyze the effects of PPJ (35.9–64.1%; v/v) and CSL (3.18–8.82%; v/v) (independent variables) on
production of fungal chitin and chitosan (dependent variable) by R. arrhizus. The extraction of chitin and chitosan was carried out using fungal biomass deproteinized with 1 M NaOH solution (1:40 w/v, 121 °C, 15 min), then the alkali-insoluble fraction was separated by centrifugation. This fraction was extracted using 2% of acetic acid (1:100 w/v, 100 °C, 15 min) followed by
centrifugation. The supernatant was obtained, and the pH was adjusted to 10, until the chitosan fraction was precipitated. Chitosan was obtained by centrifugation, washed with distilled water and freeze-dried. The highest yields of chitin (110.36 mg/g) and chitosan (59.84 mg/g) were achieved in media containing higher and intermediate concentration of PPJ (64.1% w/v) and CSL
(6.00% v/v), respectively. CSL has been shown to influence positively the chitin and chitosan productions mainly because of its high nitrogen (6.50%) and carbon (37.75%) contents, as determined by elemental analysis. In addition to the minerals found in CSL, which are necessary for fungal growth and the high carbon (37.79%) content present in PPJ. This study showed that PPJ and CSL are potential substrates to the production of chitin and chitosan by R. arrhizus through standard fermentation conditions, being an ecofriendly and low-cost alternative. Palavras-chave: biopolymers, extraction, fermentation, production, waste Agência de fomento:CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brazil e Fundação de Amparo a Ciência e Tecnologia do Estado de Pernambuco | |||||