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BACKGROUND: The demand for green products is pushing industries to search for more eco‐friendly materials, especially for food packaging applications. Starch biopolymer has been recognized as biodegradable material that can be produced from various plants. However, the strength of starch‐based bioplastic retards their widespread application. Simultaneously, the high amount of agricultural waste produced by the food industry has been a growing environmental issue. Incorporating agro‐waste fibers as a biofiller in starch‐based bioplastic can improve the properties of the bioplastic, allowing its use in various applications. Thus, this study aims to evaluate the effect of chemical treatment on the structural, thermal, and mechanical properties of sugarcane bagasse as filler for starch‐based bioplastic. RESULTS: Results showed that alkaline treatment improved surface roughness and freed it of surface impurities. Results revealed that the thermal stability and mechanical properties improved significantly with the incorporation of sugarcane bagasse (SB) loading into potato starch (PS). The highest tensile strength (5.30 MPa) and Young's modulus (28.72 MPa) were exhibited by the sample with 6% SB loading and further increments of SB led to a decrease in the strength of the biopolymer. CONCLUSION: The incorporation of alkali‐treated SB could increase and enhance the tensile strength and thermal stability of the bioplastic. This would contribute to reinforced materials that will allow for the application of PS as a new potential biodegradable material. Thus, it reduces the disposal period process and has great potential as an environmentally friendly, biodegradable, and renewable material. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

From both engineering and economic perspectives, goals of an aquaponic recirculation system are keeping a healthy environment for fish and plant, by eliminating toxic metabolites and growth-inhibiting substances. The type and quantity of waste excretions produced by the cultured organisms are also the important considerations, especially in designing the component system. Therefore, to be effective at nutrient removal, aquaponic systems should be sized correctly to balance fish output and nutrient uptake by plants. In this study, the plant component was isolated from the fish rearing operation so that nutrient removal could be evaluated independently. Two leafy green vegetables, i.e. water spinach (Ipomoea aquatica) and mustard green (Brassica juncea) were selected to evaluate the effectiveness of plant nutrient uptake to balance nutrient production from fish culture. Results indicated that nitrogen utilization efficiencies of water spinach and mustard green were 66.5 and 59.9%, respectively. In addition, water spinach-based aquaponics had better water quality than that of mustard green-based aquaponics, primarily due to its higher root surface area. The growth performance of African catfish showed the feed conversion ratio was in the range 1.18–1.33. The results obtained from this study indicated that both crops have considerable impacts on nutrient removal. [ABSTRACT FROM AUTHOR]

The physical profile and chemical composition of growing media are vital in evaluating fish waste filtration efficiency and plant growth performance in aquaponics. The present study reported and compared the physical and chemical evaluation of the novel fabricated Kaolina, gravel, and commercially used lightweight expanded clay aggregate (LECA) as growing medias in aquaponics. Field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDX) was utilized to analyze the growing media's chemical composition and structural characterization. The resultant effect of these growing medias on water quality and the growth performance of Clarias gariepinus and Lactuca sativa were also reported. Kaolina exhibited an excellent physical profile (42.95 ± 1.39%) in water absorption capacity as compared to LECA (35.90 ± 1.28%) and gravel (1.97 ± 0.25%), showing a significant difference at p < 0.05. The addition of 25% w/w Musa paradisiaca peel in the fabrication of Kaolina gives an added value of 88.0% of K and 100% of P elements, which show a significant difference (p < 0.05) compared to LECA. The results obtained reveal a better daily growth rate (DGR) and relative growth rate (RGR) of L. sativa at 0.57 ± 0.02 cm day−1 and 0.21 ± 0.00 g day−1, respectively. Results indicated that the porous structure of growing media could contribute to the high-water retention capability and slow the water desorption process. Hence, it could increase the ability of the growing media to hold nutrients for plant intake, resulting in higher removal percentage of nutrients in aquaponics system. Kaolina gives the highest nutrient removal percentage of TAN (96.86 ± 1.50%), NO 2 − (83.56 ± 1.27%), NO 3 −(77.55 ± 0.48%), and PO 4 3− (79.46 ± 0.42%). The results also shown growing media has considerable impacts on nutrient removal, which contribute to the aquaponic productions. [Display omitted] • Nutrient supplies through Kaolina are more natural and sustainable. • Kaolina eliminate chemical nutrient supply practiced in aquaponics. • Water absorption and retention capacity of Kaolina is more stable. • Kaolina provided essential micronutrients and optimized physical characteristics. • Significant yield of L. sativa and C. gariepinus in Kaolina than LECA and gravel. [ABSTRACT FROM AUTHOR]

Moringa oleifera is characterized by high coagulation properties, low cost and low toxicity hence is very promising to be utilized as an alternative coagulant to recover microalgae biomass from its suspension system. Hence, this study was performed with the objective to investigate the potentiality of M . oleifera as coagulant agent in harvesting microalgae and to investigate the effect of zeta potential in its coagulation-flocculation activity. Bradford protein assay was applied for rapid and accurate determination of protein concentration in the M . oleifera seed powder and protein powder. The flocculation activities were determined at isoelectric pH by computing the flocculation efficiency in terms of microalgae biomass recovery and removal percentage at various coagulant dosages. It was observed that the protein concentration was 211.71 μg g −1 mL −1 in M . oleifera seed powder and 188.16 μg g −1 mL −1 in protein powder which yielded 97% and 78% of biomass recovery, respectively at the dosage of 10 mg L −1 . Result showed that M . oleifera seed derivatives supersede chemical coagulant, alum which yielded 34% of biomass recovery at the same dosage. M . oleifera seed powder and protein powder was proven to be highly promising bio-coagulant and suitable alternative to the chemical coagulant in environmentally-sustainable harvesting of microalgae biomass. [ABSTRACT FROM AUTHOR]

Moringa oleifera (MO) seed has been widely used for water treatment purposes due to their good flocculation, low cost and non-toxic characteristics. However, these advantages had not yet been utilized for the microalgae harvesting technology. Until today, the harvesting of microalgae biomass still depend on sophisticated and complex approaches such as hollow fiber filtration, chemical flocculants and Alfa Laval decanter technology. Thus, in this study the potential of natural plant-based coagulant was investigated. MO seed derivatives were determined for the harvesting of suspended freshwater microalgae, Chlorella sp.. Flocculation characteristics with various dosages were optimized. The output of this study proved that primary and tertiary MO derivatives yield excellent flocculation efficiency of more than 95% at 20 min sedimentation. In fact, MO derivatives even supersede chemical flocculants, Aluminum Sulfate in terms of flocculation efficiency and biomass recovery at a low dosage of 10 mg L −1 and normal pH (6.9–7.5). Seed powder had the highest removal efficiency whereas seed protein had the highest biomass recovery. Utilization of M. oleifera derivatives as bio-coagulant provides several advantages such as lower impact on the environment, lower cost for microalgae harvesting, allow rapid microalgae culture expansion and as chemical-free green technology. [ABSTRACT FROM AUTHOR]

Bioremediation of aquaculture wastewater utilizing naturally occurring bacteria and microalgae have been widely used since 1990s in open pond. However, the relationship between both bioremediators especially in term of nutrient reduction had not been studied thoroughly in enclosed treatment system. Bioremediation of either Effective Microorganisms (EM) or microalgae (MA) independently required additional supply of oxygen and carbon dioxide, respectively to sustain their growth and treatment efficiency. Conversely, symbiotic bioremediation could omit these requirement due to the associate relation between both in term of respiration. EM bioremediation would produce CO 2 and consume O 2 whereas microalgae is vice versa. On top of that, both EM and microalgae simultaneously function as degradation of organic matter. In this study, symbiotic MA–EM showed higher removal percentage and removal rate on phosphorus of 99.15% and 0.534 mg L −1 d −1 as compared to 49.73% and 0.130 mg L −1 d −1 for the conventional MA bioremediation. However, inoculation of EM in the symbiotic MA–EM bioremediation did not significantly improved the removal of ammonia. With proper optimization of inoculation volume and bioremediation mode, symbiotic relations of these two microorganisms would benefits in designing more robust, economical and least maintenance on the wastewater treatment system. [ABSTRACT FROM AUTHOR]

Development of aquaculture industry is restricted due the undesirable environmental impact associated with the effluent discharge that is rich in inorganic nitrogenous compound and organic matters. This situation could be improved through the implementation of Bioflocs Technology (BFT). BFT can enhance the water quality in aquaculture system by introducing natural nutrient recycling characteristics with the induction of appropriate carbon/nitrogen (C/N) ratio. However, the natural condition of aquaculture system, which is rich in inorganic nitrogen, could not sustain BFT. Thus, additional carbon is required to obtain a suitable C/N ratio for effective formation of bioflocs complex. This study focused on the determination of optimum C/N ratio by varying the dosage of carbon introduced into the system. Five different C/N ratios (i.e. 10, 15, 20, 25, 30) were evaluated in treating the aquaculture system culturing Clarias gariepinus to an acceptable water quality. Bioflocs density and water quality parameters were monitored throughout the treatment period. The highest removal of ammonia was achieved at 98.7% with the formation of 92.5 mL L −1 of bioflocs concentration at an optimum C/N ratio of 15. The results show that the utilization of BFT can potentially provide a sustainable and low maintenance treatment of aquaculture system. [ABSTRACT FROM AUTHOR]

Nannochloropsis sp. and Tetraselmis sp. are widely used in aquaculture as a source of protein, lipid and carbohydrate. The growth and proximate composition of microalgae could be affected by different culture conditions especially salinity, temperature and light. Thus, this study was aimed to compare the growth and proximate composition of Nannochloropsis sp. and Tetraselmis sp. cultured in different salinities and pH under different culture conditions. In this study Nannochloropsis sp. and Tetraselmis sp. were isolated from South China Sea and cultured at different salinities of 20, 30 and 40 ppt and different pH of 5.5, 7.5, 8.5 and 9.5 under natural and control condition until stationary phase. Results showed that Nannochloropsis sp. and Tetraselmis sp. had significantly higher ( p < 0.05) cell density, lipid and carbohydrate content under control condition at 30 ppt. However, protein content was significantly higher ( p < 0.05) in Nannochloropsis sp. when cultured under natural condition at 30 ppt. High cell density, protein, lipid and carbohydrate content was obtained when cultured at pH 7.5 and 8.5 for both species. The output of this study could be considered for Nannochloropsis sp. and Tetraselmis sp. cultivation to provide appropriate levels of protein, lipid and carbohydrate as feed supplement for aquaculture organisms. [ABSTRACT FROM AUTHOR]