The Effect of Molecular Weight on the Antimicrobial Activity of Chitosan from Loligo opalescens for Food Packaging Applications

Abstract

The growing requirement for sustainable processes has boosted the development of biodegradable plastic-based materials incorporating bioactive compounds obtained from waste, adding value to these products. Chitosan (Ch) is a biopolymer that can be obtained by deacetylation of chitin (found abundantly in waste from the fishery industry) and has valuable properties such as biocompatibility, biodegradability, antimicrobial activity, and easy film-forming ability. This study aimed to produce and characterize poly(lactic acid) (PLA) surfaces coated with β-chitosan and β-chitooligosaccharides from a Loligo opalescens pen with different molecular weights for application in the food industry. The PLA films with native and depolymerized Ch were functionalized through plasma oxygen treatment followed by dip-coating, and their physicochemical properties were assessed by Fourier-transform infrared spectroscopy, X-ray diffraction, water contact angle, and scanning electron microscopy. Their antimicrobial properties were assessed against Escherichia coli and Pseudomonas putida, where Ch-based surfaces reduced the number of biofilm viable, viable but nonculturable, and culturable cells by up to 73%, 74%, and 87%, respectively, compared to PLA. Biofilm growth inhibition was confirmed by confocal laser scanning microscopy. Results suggest that Ch films of higher molecular weight had higher antibiofilm activity under the food storage conditions mimicked in this work, contributing simultaneously to the reuse of marine waste.

Nanoparticles of Lignins and Saccharides from Fishery Wastes as Sustainable UV-Shielding, Antioxidant, and Antimicrobial Biofillers

“…Wells containing microorganisms alone and OLNPs were used as a control. The procedures to determine the growth rate were the same as explained previously . The minimum inhibitory concentrations (MICs, mg/mL) were measured by growing microorganisms in the presence of different concentrations of COS/OLNPs (from 0 to 6.4 mg/mL).…”

“…The procedures to determine the growth rate were the same as explained previously. 50 The minimum inhibitory concentrations (MICs, mg/mL) were measured by growing microorganisms in the presence of different concentrations of COS/OLNPs (from 0 to 6.4 mg/mL). MIC 50 values were defined as the lowest concentration of the sample at which 50% of the bacterial growth was inhibited.…”

Antimicrobial adhesive films by plasma-enabled polymerisation of m-cresol

“…As we try to move towards a waste-free world, considerable effort and creativity have been dedicated to the transformation of waste products into useful films, such as anti-corrosion films formed from powdered egg shells on stainless steel 28 , UV-protective films made from hemp fibres and polyvinyl alcohol 29 , antioxidant and pH indication from chitosan and food waste 30 , and water barriers from biomass 31 . The incorporation of antimicrobial agents created from waste products into films such as polylactic acid or polyethylene has been reported 32 , 33 , however, descriptions of the direct synthesis of antimicrobial coatings solely from waste products is much more limited. Coatings with antimicrobial properties have been created by incorporating inorganic active agents such as silver nanoparticles 34 , molecules that activate upon contact such as peptides 35 , antibacterial agents such as antibiotics 36 , organic agents such as chitosan 37 , 38 , and materials that impact the bacterial membrane such as graphene 39 , chloramine 40 , or potassium sorbate 41 , 42 .…”

Assessment of the Antibiofilm Performance of Chitosan-Based Surfaces in Marine Environments

“…Chitosan was first extracted from endoskeleton by-products of L. opalescens squid through a combination of enzymatic and alkaline treatments, according to the conditions fully described in previous work [ 23 , 24 ]. A highly purified CS (β-CS) with an Mw of 294 kDa and a 92% degree of deacetylation was recovered and submitted to depolymerization through the reaction with sodium nitrite.…”

“…Although the antifouling activity of CS-based coatings has been reported by our group for other applications (food packaging and medical settings) [ 23 , 24 ] and short-term applications in the marine field [ 25 ], in vitro studies to test the long-term performance of CS coatings under operational conditions that simulate marine environments remain scarce. In addition, since the antimicrobial activity of CS and its derivatives depends on a set of structural properties such as molecular weight (Mw), degree of deacetylation (DD), concentration, and source [ 20 , 26 ], studies based on the physical and chemical properties of CS and their influence on biofilm formation are required for the development of more effective antifouling surfaces.…”