Chitosan is a cationic polymer obtained by deacetylation of chitin, found abundantly in crustacean, insect, arthropod exoskeletons, and molluscs. The process of obtaining chitin by the chemical extraction method comprises the steps of deproteinization, demineralization, and discoloration. To obtain chitosan, the deacetylation of chitin is necessary. These polymers can also be extracted through the biological extraction method involving the use of microorganisms. Chitosan has biodegradable and biocompatible properties, being applied in the pharmaceutical, cosmetic, food, biomedical, chemical, and textile industries. Chitosan and its derivatives may be used in the form of gels, beads, membranes, films, and sponges, depending on their application. Polymer blending can also be performed to improve the mechanical properties of the bioproduct. This review aims to provide the latest information on existing methods for chitin and chitosan recovery from marine waste as well as their applications.

This study evaluated the efficacy of coatings comprising gum arabic (GA) and essential oils from Origanum vulgare L. (OVEO) and Rosmarinus officinalis L. (ROEO) to control Rhizopus soft rot and quality of plums (Prunus domestica L.) during storage at room (25°C; 12 days) and cold (12°C; 24 days) temperatures. GA (1 mg/ml) and OVEO (0.25 μl/ml) or OVEO (0.06 μl/ml) plus ROEO (0.25 μl/ml) inhibited the mycelial growth, spore germination and sporulation of R. stolonifer. GA‐OVEO and GA‐OVEO‐ROEO coatings delayed the occurrence of soft rot and decreased the rotted plums at the end of storage compared to GA alone. Plums coated with GA‐OVEO and GA‐OVEO‐ROEO exhibited greater firmness decreased weight loss and lower decrease of sugars and phenolics at the end of storage compared to uncoated plums. GA‐OVEO and GA‐OVEO‐ROEO coatings enhanced the color and flavor, while GA‐OVEO coating affected negatively the aftertaste of plums. GA‐OVEO‐ROEO coating is a promising postharvest treatment for plums. Practical applications In plums, the reduction of postharvest quality losses resulting from decay caused by Rhizopus stolonifer contamination or by the ripening process is a major goal of postharvest technology, which increase attention to use environmental friendly methods as postharvest treatment of fruit. Edible coatings can reduce the use of synthetic fungicides, thus are in agreement with the increased consumer's demand by products obtained with the minimum quantities of synthetic products. Gum arabic is largely used in food industry, however underexplored as coating component, particularly in combination with natural antifungal substances such as essential oils. Edible coatings containing essential oils are considered environmentally friendly technologies because these substances when incorporated in polissacharydes can be released on surfaces of fruit and increase the storage time. This study evaluated coatings containing reduced amounts of oregano and rosemary essential oils in combination as postharvest treatment to control Rhizopus soft rot in plums (Prunus domestica), as well as their effects on the quality attributes of this fruit during storage. The tested coatings are presented as alternative technologies to control soft rot and preserve the quality of plums during storage.

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A biosurfactant was produced from Cunninghamella echinulata using sustainable technology for cleaning and degreasing of cotton fabric impregnated with burned motor oil. The surface tension was 32.4 mN/m on a medium containing instant noodle waste (2%), corn steep liquor (2%), and postfrying oil (0.5%) with a carbon/nitrogen ratio of 30 : 1, yield of 6.0 g·L−1, emulsifier index of 81.4%, and dispersant property of 32.15 cm2. The biosurfactant produced is a glycolipid constituted by carbohydrate (47.7%) and lipids (50.0%). The structure was confirmed by GC-MS (stearic acid in predominance with mass of 298 m/z), FTIR spectroscopy (polysaccharides in bands between 1025 and 1152 cm−1 and fatty acids in bands between 2057 and 3100 cm−1), 1H NMR, and 13C NMR spectrum (carbohydrates in signal of 4.38 ppm and 77.0 ppm). The properties of cleaning and degreasing of burned engine oil in cotton fabric by biosurfactant of C. echinulata was evidenced by removal of 86% of oil. After use of the biosurfactant, the fibers were not damaged, which is important for structural integrity of cotton fabric after the wash. In addition, the biosurfactant did not show toxic effect. This study suggests that the biosurfactant from C. echinulata can be used in formulation of textile detergents, in particular for removal of hydrophobic residues from the automobile industry.

This study evaluated corn steep liquor (CSL) and papaya peel juice (PPJ) in mixture as substrates for the cultivation (96h, 28°C, pH 5.6, 150rpm) of Mucorales fungi for chitosan production, and determined the growth-inhibitory effect of the fungal chitosan (FuCS) obtained under optimized conditions against phytopathogenic Colletotrichum species. All Mucorales fungi tested were capable of growing in CSL-PPJ medium, showing FuCS production in the range of 5.02 (Fennelomyces heterothalicus SIS 28) - 15.63mg/g (Cunninghamella elegans SIS 41). Highest FuCS production (37.25mg/g) was achieved when C. elegans was cultivated in medium containing 9.43% CSL and 42.5% PPJ. FuCS obtained under these conditions showed a deacetylation degree of 86%, viscosity of 120cP and molecular weight of 4.08×10g/mol. FuCS at 5000, 7500 and 10,000ppm inhibited the growth of all Colletotrichum species tested. FuCS also induced alterations in the morphology of C. fructicola hyphae. CSL-PPJ mixtures are suitable substrates for the cultivation of Mucorales fungi for FuCS production. Chitosan from C. elegans cultivated in CSL-PPJ medium is effective in inhibiting phytopathogenic Colletotrichum species.

The aim of the present work was to study the cadmium effects on growth, ultrastructure and polyphosphate metabolism, as well as to evaluate the metal removal and accumulation by Cunninghamella elegans (IFM 46109) growing in culture medium. The presence of cadmium reduced growth, and a longer lag phase was observed. However, the phosphate uptake from the culture medium increased 15% when compared to the control. Moreover, C. elegans removed 70%–81% of the cadmium added to the culture medium during its growth. The C. elegans mycelia showed a removal efficiency of 280 mg/g at a cadmium concentration of 22.10 mg/L, and the removal velocity of cadmium was 0.107 mg/h. Additionally, it was observed that cadmium induced vacuolization, the presence of electron dense deposits in vacuoles, cytoplasm and cell membranes, as well as the distinct behavior of polyphosphate fractions. The results obtained with C. elegans suggest that precipitation, vacuolization and polyphosphate fractions were associated to cadmium tolerance, and this species demonstrated a higher potential for bioremediation of heavy metals.