Chicken Eggshell as an Innovative Bioflocculant in Harvesting Biofloc for Aquaculture Wastewater Treatment

Implementation of biofloc technology(BFT)system in aquaculture industry shows high productivity,low feed conversion ratio,and an optimum culture environment.This study was divided into two phases.The first phase involved maintaining the water quality using the optimum carbon-to-nitrogen ratio by manipulating pH in culture water.The second phase examined the performance of harvesting biofloc(remaining phytoplankton and suspended solids in the system)using chicken eggshell powder(CESP).This study showed that pH 7 to 8 were the best biofloc performance with high removal percentage of ammonia(>99%)with a remaining ammonia concentration of 0.016 mg L^(−1)and 0.018 mg L^(−1),respectively.The second phase of this study was performed to determine the optimal formulation and conditions of using CESP as a bio-flocculant in harvesting excess biofloc.The use of eggshell showed a higher harvesting efficiency of more than 80%under the following treatment conditions:0.25 g L^(−1)of eggshell dosage;with rapid and slow mixing rates of 150 and 30 rpm,respectively;30 min of settling time;settling velocity of 0.39 mm s^(−1)and pH of 6 to 7.Therefore,the results indicated that biofloc would be the best green technology approach for sustainable aquaculture wastewater and the CESP is an organic matrix that environmental-friendly bio-coagulant for biofloc harvesting.

Extraction and Characterization of Litopenaeus vannamei’s Shell as Potential Sources of Chitosan Biopolymers

Chitin is the second most abundant polysaccharide,produced mainly as an industrial waste stream during crustacean processing.Chitin can be derived into chitosan through the deacetylation process.Conversion of shrimp waste into chitosan via the deacetylation process could be considered a practical approach for shell waste remediation.In this study,chitosan’s physicochemical characteristics extracted from two types of Pacific white leg shrimp,L.vannamei’s shell(i.e.,rough and smooth),were compared with commercial chitosan.The yield,moisture,ash,solubility,water and fat binding capacity were measured.The degree of deacetylation(DDA)was calculated using FTIR,and their chemical Structure was confirmed using XRD and SEM-EDS.Both extracted chitosan showed no significant difference in yield,moisture,ash,solubility and water binding capacity but showed a significant difference with commercial chitosan.Moreover,the fat binding capacity of commercial chitosan showed the lowest percentage(408.34±0.83%)as compared to extracted chitosan(smooth shell 549.59±12.48%;rough shell 500.55±12.10%).The DDA indicated that extracted chitosan from the smooth and rough shell was considered good chitosan as compared to commercial chitosan with 84.08±1.27%,80.78±0.79%and 74.99±1.48%,respectively.Additionally,the presence of hydroxyl and amino groups from FTIR and a good crystallinity index was recorded using XRD of extracted chitosan.Based on observed characteristics,shrimp shell waste from L.vannamei can achieve chitosan standard quality as a biopolymer and highly potential to be applied in various industrial applications.

A Review of Various Sources of Chitin and Chitosan in Nature

Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first researcher who extracted chitin from the shells of mollusks(crabs and lobsters),prawns,and crayfish in 1799.Later in 1811,Henri Braconnot discovered chitin in the cell walls of mushrooms and called it“fungine”.Chitin and chitosan are abundant in the biosphere as essential components of many organisms’exoskeletons and as by-products of the global seafood industry.The biopolymer must be deacetylated before chitosan can be produced.It can also be extracted using microbes in a biological extraction procedure.The development of products that take advantage of the bioactivities of the existing primary commercial source of chitin(crustacean)has lagged expectations.Also,the disadvantages of the present commercial source such as seasonality and competition for other uses among others has been one of the driving forces towards seeking alternative sources of chitin and chitosan in nature.This review highlights some of the efforts made by environmental scholars to locate possible commercial sources of chitin and chitosan in nature over time.

The Inhibition Effects of Alkoxyl Thiourea Derivatives toward the Growth of Isolated Oscillatoria sp. from Kenyir Lake, Terengganu

In controlling eutrophication phenomenon, there were conventional methods which lead to negative effects to aquatic environment. This study was aimed to investigate the usage of synthesized thiourea compounds to inhibit the growth of Oscillatoria sp. in Kenyir lake, Terengganu, Malaysia. The inhibition effects of four eco-friendly alkoxyl thiourea derivatives compounds named as N-（（4-（decyloxy）phenyl）carbamothioyl）-4-methyl benzamide, N-（（4-（decyloxy）phenyl）carbamothioyl）-4-nitro benzamide, 4-chloro-N-（（4-（decyloxy）phenyl）carbamothioyl） benzamide and N-（（4-（decyloxy）phenyl）carbamothioyl） benzamide were examined onto the growth culture of Oscillatoria sp. These compounds were tested in 30 mL of Oscillatoria sp. cultures with different concentration of 16 μg·mL-1, 18 μg·mL-1, 20 μg·mL-1, 24 μg·mL-1 and 28 μg·mL-1respectively. The treatment flasks were supplied with an aerator for 24 hours under continuous illumination at 25 ℃. Chlorophyll-a concentration were extracted to calculate the inhibition percentage of each treatment. Overall, all these compounds showed inhibition effects towards the growth of Oscillatoria sp., with the highest inhibition of 37% by N-（（4-（decyloxy）phenyl）carbamothioyl）-4-methyl benzamide at the concentration of 18μg·mL-1. The methyl group that attach to the synthesized compound may contribute to the effectiveness of the compound which act as an algae inhibitor. However, extensive studies still need to be conducted in order to investigate the mechanism on how this compound reacts with Oscillatoria sp..

A review of gynogenesis manipulation in aquatic animals

Gynogenesis is an established technique to generate all female type offspring and this technique has been successfully induced diploid gynogens progeny in aquatic animals of fishes and crustaceans.Monosex culture of all female shrimp and fishes were selected attribute to all female type offspring which have better size than male and help increase the market size and profitable.This article discusses on the protocol applied to produce gynogens progeny and the successful rate of gynogenesis production in fishes,molluscs and aquatic crustaceans of shrimps in general.Overall most of the UV length applied for irradiated the sperm were around 254-365 nm for(20-40 s),(20-80 s)and(5-8 s)for shrimps,254 nm,30 s for molluscs species and for fishes were around 254 nm for(1.5min)and(2-12 min)time of exposure respectively.For gynogenesis induction,the fertilized eggs were treated with cold shock,heat shock or cytochalasin-B for both shrimp and fishes gynogens technique.Fertilization rate was identified around 4.33%-19.67%in shrimp.Successful hatching rate was identified around 3.0%,14.9%-37.2%of gynogens offspring in shrimp and various percentages of hatching rates were identified from each species of fish gynogens.Overall,there is still low survival rate of gynogens produced using gynogenesis technique and further study should be carried out to improve the gynogens production.The discussed protocols serve as a guide lines for the gynogenesis technique application of all female monosex culture in the future.

Synergistic effects of Recirculating Aquaculture System(RAS)with combination of clear water,probiotic and biofloc technology:A review

Recirculating Aquaculture System(RAS)is introduced in aquaculture farming industry to reduce water resource utilization,efficient the energy and land uses,and also help minimalize the water exchange.This system enables utilization of unsuitable land and promotes a sustainable environment in aquaculture industry.Furthermore,this technology has been established and proved efficient in monitoring the aquatic animal condition subsequently helps in maintaining the water quality and help remove solid particle wastes from the aquaculture treatment.As today,RAS has been developed with more effective technologies such as the use of UV irradiation,solid capture,protein skimmer and also provided with highly techno bio-filtration set.Basically,this system was applied for broodstock maturation,nursery phase,and grow-out production.In this review article,we provide an overview of RAS between the clear water,probiotic,and biofloc technology,and the advantages of its combination.Even though RAS and biofloc is two different parallel system,the application of the probiotic and biofloc in the semi-RAS application system is intense to be investigated.The synergistic effect of RAS using this combination towards high yield aquaculture production will be highlighted in this review paper.Expectantly this review paper will generate awareness and useful information on the RAS application in the aquaculture system operation with help in maximize the impact to the aquaculture yield production.