Chitin Determination in Residual Streams Derived From Insect Production by LC-ECD and LC-MS/MS Methods

Chitin, a biopolymer present in fungi and arthropods, is a compound of interest for various applications, such as in the agricultural and medical fields. With the recently growing interest in the development of insect farming, the availability of chitin-containing residual streams, particularly the molting skins (exuviae), is expected to increase in the near future. For application purposes, accurate quantification of chitin in these insect sources is essential. Previous studies on chitin extraction and quantification often overlooked the purity of the extracted chitin, making the outcomes inconsistent and prone to overestimation. The present study aims to determine chitin content in the exuviae of three insect species mass-reared worldwide: black soldier fly (BSF), mealworm, and house cricket. Chitin was chemically extracted using acid and alkali treatments to remove minerals and proteins. The purity of extracted chitin was evaluated by hydrolyzing the chitin into glucosamine, followed by quantitative determination of the latter using two liquid chromatography methods: electrochemical detection (ECD) and tandem mass spectrometry (MS/MS). Both methods proved accurate and precise, without the need for labor-intensive derivatization steps. Pearson's correlation and Bland-Altman plots showed that the glucosamine determination results obtained by the two methods were comparable, and there is no consistent bias of one approach vs. the other. The chitin content in extracted residues ranged between 7.9 and 18.5%, with the highest amount found in BSF puparium. In summary, the study demonstrated that (1) the residual streams of the insect farming industry have a great potential for utilization as an alternative chitin source, and (2) both LC-ECD and LC-MS/MS are reliable for the quantitative determination of glucosamine in insect chitin.

Impact of FKS 1 genotype on echinocandin in-vitro susceptibility in Candida auris and in -vivo response in a murine model of infection

Objectives: Echinocandins are frontline antifungal agents in the management of invasive infections due to multi-drug resistant Candida auris . The study aimed to evaluate echinocandin resistance in C. auris isolates of multicentric origin, identify the resistance mechanism, and analyze the pharmacodynamic response to caspofungin in a neutropenic mouse model of infection. Methods : A total of 199 C. auris isolates originating from thirty centres across India were tested for susceptibility to echinocandins. Isolates with reduced susceptibility were evaluated for FKS 1 mutations and in-vivo response to caspofungin in a murine model of disseminated candidiasis. In addition, the response to echinocandins was assessed in light of in-vitro growth kinetics, chitin content; and transcript levels of chitin synthase and FKS1 genes. Results: We report 10 resistant C. auris isolates with four FKS 1 mutations: F635Y ( n =2), F635L ( n =4), S639F ( n =3), and R1354S ( n =1). Of these, F635Y and R1354S exhibited the most profound resistance in mouse model of disseminated infection. S639F and F635L mutations conferred a moderate in vivo resistance, whereas wild-type isolates exhibiting borderline MIC were susceptible in vivo . FKS 1 genotype was more accurate predictor of in-vivo response than the MIC of the isolates. Isolates with high basal or inducible chitin content exhibited higher in vitro MIC in FKS 1 mutant compared to wild-type. Conclusions FKS 1 mutations play a major role in clinically relevant echinocandin resistance in C. auris with differential in vivo outcomes. This study could have implications for clinical practice and, therefore, warrants further studies.

True grit: ingestion of small stone particles by hummingbirds in West Mexico

Background Grit is used by birds mainly for grinding hard food items but can also serve a nutritional role as a source of minerals. Ingestion of grit by birds has been documented primarily in species that feed on seeds and invertebrates. Although feeding mainly on nectar and small arthropods, hummingbirds also ingest grit, but why they do so is unclear. We quantified the number of grit particles in the stomachs of six species of hummingbirds during an annual cycle in a seasonal ecosystem of West Mexico. Methods We compared the number of grit particles in the stomachs of different hummingbird species (Mexican Violetear Colibri thalassinus, Amethyst-throated Mountaingem Lampornis amethystinus, White-eared Hummingbird Basilinna leucotis, Rivoli’s Hummingbird Eugenes fulgens, Broad-tailed Hummingbird Selasphorus platycercus, and Rufous Hummingbird S. rufus), and between sex and age categories during the different seasons of a year. To determine if grit was used to grind ingested arthropods, we examined the relationships between the number of grit particles, the biomass of arthropods ingested, and their chitin content. Results Although species did not differ in the number of grit particles in their stomachs, we found that grit was mostly ingested by female individuals, with only one male of one species (Mexican Violetear) presenting grit in its stomach. We also found that female hummingbirds had grit in their stomachs during the rainy and the cold-dry season (June–February) but not during the warm-dry season (March–May). Our analyses revealed no relationship between the number of grit particles and the amount of ingested arthropods and arthropod chitin content. However, high grit consumption was related to wasp ingestion on Mexican Violetears. Conclusions Our results indicate that grit is used mainly by female hummingbirds. The seasonal variation in the ingestion of grit by female individuals suggests that it can be used to meet mineral requirements related to breeding; however, this topic needs further exploration. Additionally, the use of grit was proportionally higher in juvenile individuals, suggesting it is used for grinding arthropods during a period of fast development.

Potensi Limbah Sisik Ikan Sebagai Kitosan dalam Pembuatan Bioplastik

<p><strong>Bioplastics are environmentally friendly plastics derived from natural materials. Bioplastics are easier to decompose when compared to commercial plastics. Bioplastics are generally made from starch contained in plants. But the use of starch as a base material has the disadvantage of producing bioplastics that are not waterproof. Therefore, it is necessary to add chitosan to improve bioplastic characteristics. Chitosan usually comes from the shell of crustacean animals, but it turns out that in fish scales waste, also contains chitosan. Fish scales are a by-product of the process of fish processing. Fish scales are only discarded and not utilized so that they become waste that can pollute the environment. Fish scales have a chitin content that can process into chitosan, which can be useful as an additional ingredient in the manufacture of bioplastics. This review aims to find out the potential of fish scales waste as chitosan in the manufacture of bioplastics. Based on the results of previous research, fish scales have a chitosan content that can use as an additional ingredient in the manufacture of bioplastics. Fish scale chitosan can form bioplastic film with characteristic brownish-yellow film. The addition of fish scale chitosan is also able to improve the water resistance of bioplastic film. Based on the results of the review can be concluded bring fish scales to have the potential as chitosan that can use in the manufacture of bioplastic.</strong></p><p><strong>Keywords –</strong> <em>Bioplastic, Chitosan, Fish Scales.</em></p><p> </p>

Preparation of Cellulose/Chitin Blend Materials and Influence of Their Properties on Sorption of Heavy Metals

A series of biodegradable cellulose/chitin materials (beads and membranes) were successfully prepared by mixing cellulose with chitin in an NaOH/thiourea–water system and coagulation in a H2SO4 solution. The effects of chitin content on the materials’ mechanical properties, morphology, structure, and sorption ability for heavy metal ions (Pb2+, Cd2+, and Cu2+) were studied by tensile tests, scanning electron micrographs, Fourier transform infrared spectroscopy, and atomic absorption spectrophotometry. The results revealed that the cellulose/chitin blends exhibited relatively good mechanical properties, a homogeneous, microporous mesh structure, and the existence of strong hydrogen bonds between molecules of cellulose and chitin when the chitin content was less than 30 wt%, which indicated a good compatibility of the cellulose/chitin materials. Furthermore, in the same chitin content range, Pb2+, Cd2+, and Cu2+ can be adsorbed efficiently onto the cellulose/chitin beads at pH0 = 5, and the sorption capacity of the beads is more than that of chitin flakes. This shows that the hydrophilicity and microporous mesh structure of the blends are favorable for the kinetics of sorption. Preparation of environmentally friendly cellulose/chitin blend materials provides a simple and economical way to remove and recover heavy metals, showing a potential application of chitin as a functional material.

Shellfish Chitosan Potential in Wine Clarification

Chitosan is a chitin-derived fiber, extracted from the shellfish shells, a by-product of the fish industry, or from fungi grown in bioreactors. In oenology, it is used for the control of Brettanomyces spp., for the prevention of ferric, copper, and protein casse and for clarification. The International Organisation of Vine and Wine established the exclusive utilization of fungal chitosan to avoid the eventuality of allergic reactions. This work focuses on the differences between two chitosan categories, fungal and animal chitosan, characterizing several samples in terms of chitin content and degree of deacetylation. In addition, different acids were used to dissolve chitosans, and their effect on viscosity and on the efficacy in wine clarification were observed. The results demonstrated that even if fungal and animal chitosans shared similar chemical properties (deacetylation degree and chitin content), they showed different viscosity depending on their molecular weight but also on the acid used to dissolve them. A significant difference was discovered on their fining properties, as animal chitosans showed a faster and greater sedimentation compared to the fungal ones, independently from the acid used for their dissolution. This suggests that physical–chemical differences in the molecular structure occur between the two chitosan categories and that this significantly affects their technologic (oenological) properties.

Black Soldier Fly (Hermetia illucens) Prepupa Phase Fermentation by Organic Acids to Decrease Chitin Content

Black Soldier Fly has high protein but there are anti-nutrients, namely the presence of chitin content that cannot be digested by livestock such as poultry and monogastrics. Chitin is a natural polysaccharide that is abundantly found from crustacean organisms and insects. Chitin is usually bound to the shell or exoskeleton, proteins, minerals and pigments. Black Soldier Fly in the prepupa phase has high protein, dark brown body and a rather hard exoskeleton which causes a high chitin content. The aim of this research was to determine the concentration of propionic and formic acids which could reduce the chitin content of the prepupa phase of the Black Soldier Fly (Hermetia illucens) fermentation. This study used a completely randomized design (CRD) with five treatments, namely P1 = (BSF added 50% propionic acid + 50% formic acid), P2 = (BSF added 80% propionic acid and formic acid + 20% aquadest), P3 = (BSF added 60% propionic and formic acids + 40% aquadest), P4 = (BSF added 40% propionic and formic acids + 60% aquadest), P5 = (BSF added 20% propionic acid and formic acid + 80% aquadest) with three repetitions. The results of this study indicate that the P1 treatment (addition of 50% propionic acid + 50% formic acid) resulted in the lowest reduction in chitin content, namely (11.00%), pH value (4.7), total titrated acid (0.014%) and organoleptic (light brown color, very sour aroma and harsh texture).

Shellfish Chitosan Potential in Wine Clarification

Chitosan is a chitin-derived fiber, extracted from the shellfish shells, a by-product of fish industry, or from fungi grown in bioreactors. In oenology, it is used for the control of Brettanomyces spp., for the prevention of ferric, copper and protein casse and for clarification. The International Organisation of Vine and Wine established the exclusive utilization of fungal chitosan to avoid the eventuality of allergic reactions. This work focuses on the differences between two chitosan categories, fungal and animal chitosan, characterizing several samples in terms of chitin content and degree of deacety-lation. In addition, different acids were used to dissolve chitosans, and their effect on viscosity and on the efficacy in wine clarification were observed. Results demonstrated that, even if fungal and animal chitosans shared similar chemical properties (deacetylation degree and chitin content), they showed different viscosity depending on the acid used to dissolve them. A significant difference was discovered on their fining properties, as animal chitosans showed a faster and greater sedimentation compared to the fungal, independently from the acid used for their dissolution. This suggests that physic-chemical differences in the molecular structure occur between the two chitosan categories and that this affect significantly their technologic (oenological) properties.