Screening factors affecting chitosan extraction from mud crab (Scylla sp.) shell using microwave irradiation for the Response Surface Approach

Extracting chitosan from crab shell using conventional method requires processing in strong acid and alkali conditions under high temperature with long reaction time. Microwave-based extraction proposes shorter processing time, and hence energy and cost efficient. This study intended to screen factors affecting the extraction of chitosan from mud crab shell using microwave irradiation. The factors would be used in Response Surface Methodology (RSM) approach to obtain the optimum conditions for chitosan extraction. Microwave irradiation was employed in all of the three steps of chitosan extraction, the demineralization, deproteination, and deacetylation processes. A fractional factorial design was used to screen eight independent factors to determine the most significant ones to be optimized to determine the maximum value of four responses, which were yield, mineral removal, degree of deacetylation and moisture content. The results show that all of the main independent variables were significant in affecting minimal one of the 4 responses (P < 0.05). Mud crab chitosan had the degree of deacetylation of 87.72 – 95.13 %. Results of the screening analysis concluded, the main independent factors that are going to be applied in the optimization study are NaOH concentration, microwave oven power, and reaction time in deacetylation process.

Making nanostructured materials from maize, milk and malacostraca

Nano-structured materials are used in electronics, diagnostics, therapeutics, smart packaging, energy management and textiles, areas critical for society and quality of life. However, their fabrication often places high demands on limited natural resources. Accordingly, renewable sources for the feedstocks used in their production are highly desirable. We demonstrate the use of readily available biopolymers derived from maize (zein), milk (casein) and malacostraca (crab-shell derived chitin) in conjunction with sacrificial templates, self-assembled monodisperse latex beads and anodized aluminium membranes, for producing robust surfaces coated with highly regular hyperporous networks or wire-like morphological features, respectively. The utility of this facile strategy for nano-structuring of biopolymers was demonstrated in a surface based-sensing application, where biotin-selective binding sites were generated in the zein-based nano-structured hyperporous network.

Multielemental Determination of Rare Earth Elements in Seawater by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) After Matrix Separation and Pre-concentration With Crab Shell Particles

Considering the unique characteristics of rare earth elements (REEs), the presence of REEs beyond specific limits will adversely affect the environment and it can be employed as a powerful probe for investigating hydrogeochemical processes. This requires sensitive determination of REEs in natural seawater. A matrix separation and pre-concentration technique using the mini-column packed with crab shell particles (CSPs) by inductively coupled plasma mass spectrometry (ICP-MS) as a means of determination has been developed. The aim of the proposed method was to simultaneously determine 16 REEs (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) at trace or ultra-trace concentrations in seawater. The biosorption capacity of CSPs was found to achieve 1.246–1.250 mg g−1 for all elements. In order to optimize performance of the method, the effects of analytical parameters concerning oscillation time, solution pH, salt concentration and eluent concentration were explored. Under the optimal conditions, the detection limits of REEs ranged 0.0006–0.0088 μg L−1, and relative standard deviations (n = 7) varied between 0.55 and 1.39%. The accuracy of developed method was evidenced by applying it to the analysis of REEs in seawater samples, with the overall recoveries at a level of 95.3 and 104.4%. Together, this work provides a promising and cost-effective CSPs-based pretreatment approach for REEs detection in sea environment.

Literature review: Economic value of utilization of crab shell waste (Case study of PT. Toba Surimi Industri in Tanjungpinang City, Riau Island Province)

Writing this scientific paper aims to determine the economic value of the potential waste of crab shells produced by PT. Toba Surimi Industry in Tanjungpinang City, Riau Islands Province. The company has not utilized crab shell waste. In contrast, crab shell waste can provide economic value that provides a lot of additional value. Crab shell waste can be processed into chitosan, which has many functions in various sectors, both in the fisheries, automotive and health industries, and other sectors. Chitosan is produced from the chitin substance contained in crab shells through deproteination, demineralization, and deacetylation. The economic value that can generate from the utilization of crab shell waste PT. Toba Surimi Industry when processed into chitosan with a crab shell weight of 270 kg/day, which is Rp. 40.500.000/day.

The Use of Different Deacetylation Temperature Toward Quality of Chitosan Mud Crab Shell (Scylla serrata)

This research aims to determine the chemical composition (proximate) of chitosan and chitin, The best deacetylation temperature for obtaining chitosan, and the yield of chitosan and chitin from mud crab. This research was conducted in two stages, that is: 1) Preparation of mud crab flour and 2) Extraction and analysis of chitin and chitosan. The experimental design used for chitosan isolation was Completely Randomized Design (CRD). The process of deacetylation chitin becomes chitosan by using 50% NaOH with varying heating temperatures (120, 130, and 140°C). Parameters observed were yield, moisture content, ash content, and degrees of deacetylation. The result showed that the best chitosan was obtained by chitin deacetylation process into chitosan using a temperature of 130°C (KO2). Characteristics quality of the chitosan mud crab shell produced are KO1: yield 61.00%, moisture content 6.47%, ash content 17.18% (db), and degree of deacetylation 49.63%. KO2: yield 59.94%, moisture content 6.48%, ash content 14.85% (db) with degree of deacetylation 51.13%. KO3: yield 53,97, moisture content 6.54%, ash content 14.66% (db) and degree of deacetylation 52.63%. Characteristic quality of chitin included yield was 27.81%, moisture content 7.29%, ash 44.05%, and degree of deacetylation 33.09%.

Adsorption of Reactive Dye onto Uçá Crab Shell (Ucides cordatus): Scale-Up and Comparative Studies

The growing interest in using low-cost methods that use natural sources makes the study of adsorption processes increasingly frequent and common. Thus, the use of uçá crab shell (Ucides cordatus) in the adsorption of reactive dye (reactive blue 222) was studied in two systems (S1 and S2) in a finite bath, with a scale-up of 12 times and considering different forms of agitation. The biosorbent material was previously characterized from FTIR and EDX spectroscopies, SEM, physical adsorption of N2, and point of zero charge. The kinetic study allowed modeling the experimental data and defining the equilibrium time for the S1 system as 400 min, and the S2 system as 360 min. The equilibrium adsorption capacities are 3.623 mg·g−1 (S1) and 4.191 mg·g−1 (S2). The pseudo-second-order (PSO) model best described the experimental data. The favorable multilayer adsorption was confirmed for the isothermal analysis, and the Freundlich and Sips models represented the experimental data of S1 and S2, respectively. The results obtained are positive indications of the scale-up of the S2 system.