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Biofloc technology improves water quality and promote the growth of beneficial bacteria community in shrimp culture. However, little is known about the bacteria community structure in both water and gut of cultured organisms. To address this, the current study characterised the metagenomes derived from water and shrimp intestine samples of novel Rapid BFTTM with probiotic and clearwater treatments using 16S V4 region and full length 16S sequencing. Bacteria diversity of water and intestine samples of Rapid BFTTM and probiotic treatments were similar. Based on the 16S V4 region, water samples of >20 mm biofloc had the highest abundance of amplicon sequence variant (ASV). However, based on full length 16S, no clear distinction in microbial diversity was observed between water samples and intestine samples. Proteobacteria was the most abundant taxon in all samples based on both 16S V4 and full length 16S sequences. Vibrio was among the highest genus based on 16S V4 region but only full length 16S was able to discern up to species level, with three Vibrios identified--V. harveyi, V. parahaemolyticus and V. vulnificus. Vibrio harveyi being the most abundant species in all treatments. Among water samples, biofloc water samples had the lowest abundance of all three Vibrios, with V. vulnificus was present only in bioflocs of <20 mm. Predicted functional profiles of treatments support the beneficial impacts of probiotic and biofloc inclusion into shrimp culture system. This study highlights the potential displacement of opportunistic pathogens by the usage of biofloc technology (Rapid BFTTM) in shrimp culture. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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]