Use of chitosan for the removal of metal ion contaminants and proteins from water

Chitin is the second most abundant natural biopolymer after cellulose and is distributed in the shells of crustacea and cuticle o f insects and also in the cell wall of some fungi. Chitosan is the deacetylated product of chitin. Chitosan has been used in a number of fields such as agriculture, the food industry and medicine. Both chitin and chitosan are recognized as excellent metal ligands, forming stable complexes with many metal ions. In particular, chitosan is considered one of the best natural chelators for transition metal ions and an effective protein coagulating agent. The processing discards of shellfish pose major technological problems, mainly due to their insolubility in water and resistance to biodegradation. Direct use o f crab processing discards is generally discouraged due to the obnoxious odour of putrefying shells, therefore, value-added utilization of their discards is of paramount importance. In the treatment of crab processing discards to extend their usable shelf-life, five different chemical treatments were used. Fresh samples of crab processing discards were treated by dipping in 1 % formaldehyde, formic acid, acetic acid, sodium bicarbonate or sodium hydroxide solution. Experiments were con.d ucted at two temperatures ranges; 4- 7°C and 20-25°C. The samples were evaluated for sensory characteristics by a seven - membered panel and the results were recorded. Chitin isolated from crab processing discards was deacetylated in order to produce three types of chitosan (Types 1, 2 and 3). Chitosans so prepared were evaluated for their capacity to chelate single metal ion solutions containing Co²⁺, Fe²⁺, Ni²⁺, Cd²⁺, Mn²⁺, Zn²⁺ and Cu²⁺. Then, the three chitosan types were tested for their capacity to chelate metal ions in samples of water obtained from a zinc minining site, Buchans, Newfoundland. Ethylenediaminetetraacetic acid (EDT A) was used as the reference chelating agent. The capacity to chelate single metal ions by chitosan and EDTA was determined by a colourimetric method and metal chelation capacity of wastewater was determined by inductively coupled plasma-mass spectrometry (ICP-MS) at three pH levels (5,6 and 7). Chelation and recovery of metals from aqueous solutions using a column containing chitosan was also determined by ICP MS. Ethylenediaminetetraacetic acid was used to recover metal ions that were chelated by chitosan in the column. Chitosan served as an effective coagulating agent in removing proteins from waste water. Out of the tested treatments, 1 % formaldehyde served best in controlling the foul odour development both at 4-7°C and 20-25°C followed by formic acid. Due to possible carcinogenicity of formaldehyde, formic acid could be best utilized in controlling foul odour of crab wastes. At all pH levels tested, EDTA exhibited the highest chelation capacity. At pH 5, chitosan served best for metal ion chelation and pH 7 was best for metal mixtures in waste water. Metal chelation by a column method for single metal ions showed over 98% chelation both at 50 and 100 ppm except for Co²⁺ while gave a metal recovery of 52-97%. For mixtures of metal ions, except Co²⁺, exhibited 94% chelation and metal recovery was 24-90%. Chitosan Type 1 showed the best protein flocculation ability followed by Types 2 and 3 chitosan. Encouraging results for metal chelation and recovery by the prepared chitosan and protein flocculation reveal that crustacean processing discards can be converted to useful environmentally friendly material for wastewater purification

Starch-Based Hybrid Nanomaterials for Environmental Remediation

Environmental pollution is becoming a major global issue with increasing anthropogenic activities that release massive toxic pollutants into the land, air, and water. Nanomaterials have gained the most popularity in the last decades over conventional methods because of their high surface area to volume ratio and higher reactivity. Nanomaterials including metal, metal oxide, zero-valent ions, carbonaceous nanomaterials, and polymers function as adsorbents, catalysts, photocatalysts, membrane (filtration), disinfectants, and sensors in the detection and removal of various pollutants such as heavy metals, organic pollutants, dyes, industrial effluents, and pathogenic microbial. Polymer-inorganic hybrid materials or nanocomposites are highly studied for the removal of various contaminants. Starch, a heteropolysaccharide, is a natural biopolymer generally incorporated with other metal, metal oxide, and other polymeric nanoparticles and has been reported in various environmental remediation applications as a low-cost alternative for petroleum-based polymers. Therefore, this chapter mainly highlights the various nanomaterials used in environmental remediation, starch-based hybrid nanomaterials, and their application and limitations

Impact of rice husk charcoal application on soil properties and growth and yield of rice

Fertilizer application in rice farming is an indispensable requirement. Most of the high yielding varieties which are extensively grown throughout the country require recommended levels of fertilizers in order to obtain their potential yields. Therefore, effective and efficient ways of fertilizer application are important. Coated fertilizers are used to improve the efficiency of fertilizer. However, the conventional coated fertilizers such as sulphur coated urea and urea super granules are not popular among the rice farmers in Sri Lanka owing to high cost of the coated fertilizers. One of the most sustainable solutions is application of paddy husk charcoal as a coating material to absorb N fertilizer which release nitrogenous compounds and making them available for plants. Objective of this study was to evaluate paddy husk charcoal coated urea as a slow releasing fertilizer and compare the total N and organic matter in soil and yield of paddy production. A pot experiment was carried out at Meewathura Research field in Yala 2010. Five treatments were used for twenty pots each replicated 4 times, chemical fertilizer only (Treatment 1), paddy husk charcoal coated urea only (Treatment 2), chemical fertilizer with paddy straw compost only (Treatment 3), rice husk charcoal urea with rice straw compost (Treatment 4) and no fertilizer as the control (Treatment 5). One third of urea from the recommended fertilizer was used for the treatment 2 and 4. The soil sampling  was done once a week for three months period. The mean total dry biomass for treatment 4 was significantly higher than the means for all other treatments. Considering treatment 2 and 4, rice grain yield was significantly greater in treatments 4 (charcoal  coated urea with rice straw compost). Therefore, using charcoal coated urea reduce the two third of urea usage and save 70% fertilizer cost.rice husk charcoal coated urea can potentially be used as a slow releasing nitrogen fertilizer which reduces leaching losses of urea. Key words: Charcoal, slow releasing N fertilizer, coated fertilizers, compos

Effects of Rice Husk Biochar Coated Urea and Anaerobically Digested Rice Straw Compost on the Soil Fertility, and Cyclic Effect of Phosphorus

Fertilizer application in rice farming is an essential requirement. Most of the high-yielding varieties which are extensively grown throughout the country require recommended levels of fertilizers to obtain their potential yields. However, effective, and efficient ways of fertilizer application are of utmost importance. Coated fertilizers are used to reduce leaching nutrients and improve the efficiency of fertilizer. However, conventional coated fertilizers such as Sulphur coated urea and urea super granules are not popular among rice farmers in Sri Lanka owing to the high cost. Mixing urea-coated rice husk biochar causes a slow release of nitrogen fertilizer. This coated fertilizer and rice straw compost reduction the cost of importations of nitrogen-based fertilizers per unit area of cultivation. The study aimed to evaluate the effects of rice husk biochar coated urea and anaerobically digested rice straw compost on the soil fertility, and the cyclic effect of phosphorus. Concerning the pot experiment, rice grain yield was significantly higher in Rice husk biochar coated urea, triple super phosphate (TSP), and muriate of potash (MOP) with anaerobically digested rice straw compost. The lowest yield was observed in the control. The release of phosphate shows a cycle effect which is an important finding. Rice husk biochar coated urea can potentially be used as a slow-releasing nitrogen fertilizer. In addition, the urea coated with biochar is less costly and contributes to mitigating pollution of water bodies by inorganic fertilizers (NPK)

Apiaceae Family as a Valuable Source of Biocidal Components and their Potential Uses in Agriculture

Synthetic chemicals are used to protect crops and agricultural products, thereby producing high yields. However, intensive use of these synthetic chemicals significantly affects the environment and sustainable agriculture production. Moreover, direct or indirect exposure to these synthetic chemicals may cause acute or chronic toxicity in humans and animals. Due to their biodegradability, low toxicity, and being environmentally friendly, secondary metabolites derived from plant sources are being studied as a sustainable approach. Apiaceae family crops are a good source of bioactive phytochemicals. Many studies have found that Apiaceae extracts and essential oils possess various biocidal activities: antibacterial, antifungal, herbicidal, insecticidal or repellent, and larvicidal activities, among others. These various potent bioactivities make the Apiaceae an excellent alternative source for synthetic chemicals. In this context, the present review highlights the biocidal activities of some Apiaceae species and their potential applications in agriculture to protect the plant and agricultural products against pests, weeds, phytopathogens, and foodborne and food spoilage microorganisms

Production of Single-Cell Protein from Fruit Peel Wastes Using Palmyrah Toddy Yeast

Single-cell protein (SCP) from agro-waste material has gained increased attention in the recent past as a relatively cheap and alternative protein source to meet the nutritional demand generated by the fast-growing population. Furthermore, bioconversion of these wastes into SCP such as value-added products reduce the environmental-related issues. In this study, locally available pineapple (Ananas comosus), watermelon (Citrullus lanatus), papaya (Carica papaya), sour orange (Citrus medica), banana (Musa acuminata) and mango (Mangifera indica) peel wastes were investigated for their suitability to produce SCP using palmyrah (Borassus flabellifer) toddy carrying natural mixed yeast and bacteria culture under liquid state fermentation system. Moreover, this study attempted to select the best substrate and the optimized process condition for SCP production to increase the protein yield. The physicochemical properties of selected fruit peels were analyzed. The sterilized peel extracts (10%, v/v) were inoculated with 5 mL of palmyrah toddy and allowed to ferment in a shaking incubator at 100 rpm for 48 h in triplicate At the end of fermentation, the sediments were collected by centrifugation at 1252× g, oven-dried, and the dry weight was taken to determine the protein content. The biomass yield ranged from 5.3 ± 0.6 to 11.7 ± 0.8 g/L, with the least biomass yield being observed with watermelon peels while the maximum yield was observed with papaya peels. Papaya peel generated a significantly higher (p < 0.05) amount of protein (52.4 ± 0.4%) followed by pineapple (49.7 ± 1.3%), watermelon (45.2 ± 0.7%), banana (30.4 ± 0.6%), sour orange (29.5 ± 1.2%) and mango (24.6 ± 0.2%) peels. The optimum condition for the fermentation of papaya waste was pH 5.0, 25 °C, and 24 h. Nucleic acid reduction treatment significantly reduces dry weight and protein content of biomass. It can be concluded that papaya peel waste is a suitable substrate for protein-rich cell biomass production using the natural toddy mixed culture of palmyrah

Apiaceae as an Important Source of Antioxidants and Their Applications

The excess level of reactive oxygen species (ROS) disturbs the oxidative balance leading to oxidative stress, which, in turn, causes diabetes mellites, cancer, and cardiovascular diseases. These effects of ROS and oxidative stress can be balanced by dietary antioxidants. In recent years, there has been an increasing trend in the use of herbal products for personal and beauty care. The Apiaceae (previously Umbelliferae) family is a good source of antioxidants, predominantly phenolic compounds, therefore, widely used in the pharmaceutical, cosmetic, cosmeceutical, flavor, and perfumery industries. These natural antioxidants include polyphenolic acids, flavonoids, carotenoids, tocopherols, and ascorbic acids, and exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis, and anticancer. This review discusses the Apiaceae family plants as an important source of antioxidants their therapeutic value and the use in cosmetics

Single Cell Protein Production Using Different Fruit Waste: A Review

International audienceThe single cell protein (SCP) technique has become a popular technology in recent days, which addresses two major issues: increasing world protein deficiency with increasing world population and the generation of substantial industrial wastes with an increased production rate. Global fruit production has increased over the decades. The non-edible parts of fruits are discarded as wastes into the environment, which may result in severe environmental issues. These fruit wastes are rich in fermentable sugars and other essential nutrients, which can be effectively utilized by microorganisms as an energy source to produce microbial protein. Taking this into consideration, this review explores the use of fruit wastes as a substrate for SCP production. Many studies reported that the wastes from various fruits such as orange, sweet orange, mango, banana, pomegranate, pineapple, grapes, watermelon, papaya, and many others are potential substrates for SCP production. These SCPs can be used as a protein supplement in human foods or animal feeds. This paper discusses various aspects in regard to the potential of fruit wastes as a substrate for SCP production

Seaweeds as a Source of Functional Proteins

International audienceProtein is one of the major macronutrients essential in human nutrition. Protein sources especially animal sourced proteins are expensive, thus much work has been carried out to explore alternative protein sources. Seaweeds, or macroalgae, are emerging as one of the alternative protein sources. They are rich in protein with an excellent amino acid profile comparable to the other conventional protein sources. Seaweed protein contains bioactive components, such as free amino acids, peptides, lectins, and phycobiliproteins, including phycoerythrin and phycocyanin, among others. Seaweed proteins have been proved for their antihypertensive, antidiabetic, antioxidant, anti-inflammatory, antitumoral, antiviral, antimicrobial, and many other beneficial functional properties. Therefore, seaweed proteins can be a natural alternative source for functional food development. This paper discusses the compositional and nutritional aspects of seaweed protein, protein extraction techniques, functional properties of various seaweed proteins, as well as their safety for new product development and functional food applications

Applications of Starch Biopolymers for a Sustainable Modern Agriculture

Protected cultivation in modern agriculture relies extensively on plastic-originated mulch films, nets, packaging, piping, silage, and various applications. Polyolefins synthesized from petrochemical routes are vastly consumed in plasticulture, wherein PP and PE are the dominant commodity plastics. Imposing substantial impacts on our geosphere and humankind, plastics in soil threaten food security, health, and the environment. Mismanaged plastics are not biodegradable under natural conditions and generate problematic emerging pollutants such as nano-micro plastics. Post-consumed petrochemical plastics from agriculture face many challenges in recycling and reusing due to soil contamination in fulfilling the zero waste hierarchy. Hence, biodegradable polymers from renewable sources for agricultural applications are pragmatic as mitigation. Starch is one of the most abundant biodegradable biopolymers from renewable sources; it also contains tunable thermoplastic properties suitable for diverse applications in agriculture. Functional performances of starch such as physicomechanical, barrier, and surface chemistry may be altered for extended agricultural applications. Furthermore, starch can be a multidimensional additive for plasticulture that can function as a filler, a metaphase component in blends/composites, a plasticizer, an efficient carrier for active delivery of biocides, etc. A substantial fraction of food and agricultural wastes and surpluses of starch sources are underutilized, without harnessing useful resources for agriscience. Hence, this review proposes reliable solutions from starch toward timely implementation of sustainable practices, circular economy, waste remediation, and green chemistry for plasticulture in agriscienc