ERADICATION OF MICROPLASTICS POLLUTION USING BIOFLOCCULANT-PRODUCING BACTERIA AS BIODEGRADER ISOLATED FROM BIOFLOC-BASED SYSTEM

Zuhayra Nasrin Ahmad Shukri¹, Shahadat Hossain¹, Rohisyamuddin Othman¹, Amyra Suryatie Kamaruzzan¹, Nor Azman Kasan^*1,2

¹Higher Institution Centre of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

²Microplastic Research Interest Group (MRIG), Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

^*Corresponding author: norazman@umt.edu.my

The abundance of microplastics in the natural environment is a major concern for the global ecosystem and has emerged as worldwide issue. Thus, the purpose of this research was to investigate a novel microbial strain that had been isolated from a biofloc-based system, thereby devise an environmentally friendly approach to enhance the biodegradability of commercial microplastics under laboratory conditions. The isolated bioflocculant-producing bacteria were screened using Yeast Peptone Sugar (YPG) agar and enrichment liquid media revealed a highly mucoid and ropy colonies, respectively. Two bioflocculant-producing bacteria strains, namely Microbacterium chocolatum and Microbacterium kyunghensee were isolated and tested to determine their potential as microplastic biodegrader. Screening the capability of the M. chocolatum and M. kyunghensee were done by zone of clearance method and showed the positives results. The microplastics were then incubated with M. chocolatum and M. kyunghensee in mineral salt media (MSM) for 50 days. The biodegradation extent on the microplastics were analyzed including weight loss analysis gravimetrically, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Individual weight loss indicated that M. chocolatum degraded 7.9 %, 7.0 % and 5.8 % of polyethylene, polypropylene and polystyrene, while M. kyunghensee degraded 6.0 %, 5.9 % and 4.0 % of PE, PP and PS respectively after 50 days. FTIR analysis revealed the appearance of new functional groups attributed to hydrocarbon degradation after incubation with the bacteria. Whilst, the results were confirmed again using SEM analysis which showed morphological changes on the surface of microplastic samples. Thus, the significance of these findings goes beyond the discovery of a novel function of bioflocculant-producing bacteria strain, Microbacterium sp., highlighting a potential solution for microplastics biodegradation.

Keywords: Bioflocculant-producing bacteria, Microbacterium chocolatum, Microbacterium kyunghensee, Microplastic, Biodegradation

ISOLATION AND SELECTION OF PURPLE NON-SULFUR BACTERIA FOR AQUACULTURE USES

Giang T. Huynh¹, Hai H. Vu¹, Ngan N.K Nguyen^2*

¹Department of Hydrobiology, College of Aquaculture and Fisheries, Can Tho University

²Advanced Aquaculture Program, Course 44, College of Aquaculture and Fisheries, Can Tho University

* Corresponding author: Nganb1800901@student.ctu.edu.vn

Purple non-sulfur bacteria are facultative photosynthetic bacteria and have potential use as bioremediators in aquaculture. The aim of this study was to isolate and characterize the PNSB from pond sediment and water for aquaculture uses. The results showed that a total of 31 bacterial isolates was selected from sediment and water samples of extensive shrimp ponds in Ca Mau, Bac Lieu, and Tra Vinh provinces. Most of isolates were gram-negative and grew well glutamate acetate broth displaying in pink, red or brown culture under microaerobic-light conditions. Among isolates, eight isolates were selected based on in vitro growth in rearing water from shrimp farm under both microaerobic-light and aerobic-dark conditions, and showed amylolytic and proteolytic activities. Especially, strains of CM3.1N, CM5.2N and CM4.1N were found to be the highest activities. Of interest, all of eight isolates showed ammonium removal activity with the values in a range of 53.8%-78.5% after 5 days of incubation, of which CM5.2N strain was consider to be a promising candidate for further study as well as its application in water treatment in aquaculture systems. The details of the results will be orally presented in the conference.

Keywords: Isolation, Purple non-sulfur bacteria, Enzyme activities, Ammonium removal, Water treatment.

PROPHYLACTIC EFFECTS OF Pandanus tectorius LEAF EXTRACT IN THE BRINE SHRIMP ARTEMIA-VIBRIO CHALLENGE MODEL

Patabandi PPSK^1,2, Kartik Baruah³, Parisa Norouzitallab^4,5, Yeong Yik Sung¹

¹Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia

²Department of Livestock Production, Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya, Sri Lanka

³Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, 75007, Uppsala, Sweden

⁴Lab of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium

⁵Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium

^*Corresponding author: yeong@umt.edu.my

The shrimp aquaculture sector has grown fast across the world, with yearly production increasing due to improved culture procedures. Despite the industry's growing success, disease has been one of the major causes of significant output loss, costing billions of dollars each year. Because chemical-based treatments, like as antibiotics, have previously been criticised for their negative effects on aquaculture applications, the environment, and human health, eco-friendly and more sustainable preventive and therapeutic options have attracted substantial attention. Plant-based compounds are gaining popularity as their multiple advantages in aquaculture applications have been discovered. The brine shrimp Artemia franciscana was cultured under gnotobiotic conditions as a model system to investigate the efficiency of crude leaf extract of the plant Pandanus tectorius to increase tolerance against Vibrio campbellii.  It was found that pre-exposure (priming) of Artemia to the plant extract protects against V. campbellii and induces the expression of host’s immune-related genes. Furthermore, in vitro investigations on pathogenic V. campbellii and Artemia continuous exposure trials indicated that the crude extract had antibacterial properties, reducing bacteria growth at specific concentrations. This indicates that P. tectorius leaf extract might play an important role in developing a holistic disease prevention strategy in shrimp aquaculture.

Keywords: Pandanus leaf crude extract, Gnotobiotic, Brine shrimp Artemia, Antimicrobial properties, Immune genes

TAXONOMIC AND FUNCTIONAL ANALYSIS OF GUT MICROBIOME IN WILD AND DOMESTICATED BROODSTOCK POPULATION OF BLACK TIGER SHRIMP (Penaeus monodon)

Shumpei Iehata^1*, Zulaikha Mat Deris ², Li Lian Wong ^2,3

¹Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia

²Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

³⁵UMT-OUC Joint Academic Center for Marine Studies, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia

^*Corresponding author: shumpei@umt.edu.my

Gut microbiome variation has functional importance on host health, ecology, and evolution, but the scope and basis of this diversity for marine shrimp are still not fully understood. We conducted 16S rRNA gene amplicon sequencing analysis to characterize the gut microbiomes of five Penaeus monodon broodstocks populations of wild and aquaculture environments. Diversity analysis showed the divergent bacterial diversity between wild and domesticated populations. Bacterial community composition of wild population showed unique from the location, whereas those of domesticated sample showed comparatively similar composition each other. These results indicated considerable variation in the gut microbiomes of wild and cultured shrimps, presumably reflecting differences in diet and/or host genetic divergence. Moreover, LEfSe analysis suggested that certain bacterial gene become the possible biomarker, since some probiotics candidates like genus Bacillus, Lactobacillus and Enterococcus enriched in wild population samples, whereas opportunistic pathogen such as genus Vibrio and Tenacibaculum detected highly abundance from cultured population samples. Predicted functional analysis result showed that several predicted functions had tendency to their population type. Some hydrocarbon degrading functions are enriched in wild population, whereas nitrate reduction was higher abundance in domesticated population samples. In conclusion, our results provide the insights into the deterministic factors contributing to the interpopulation variation in the P. monodon microbiome, highlighting potential future research directions in areas such as host-bacteria relationship.

Keywords: 16S rRNA gene, amplicon sequencing, aquaculture, bacterial diversity, black tiger shrimp

3R FOR CLIMATE SMART AQUACULTURE IN THE LOWER MEKONG DELTA OF VIETNAM

Kabir K A^1,2*, Schrama J W², Mortillaro J M¹, Verdegem M C J²

¹UMR ISEM - AquaBios, CIRAD, Montpellier, France

² Aquaculture and Fisheries Group, Wageningen Institute of Animal Sciences, Wageningen University and Research, Wageningen, The Netherlands

^*Corresponding author: kazi.kabir@cirad.fr

Vietnam is one of the leading aquaculture producers, producing ~5 ton per ha per year, slightly higher than global average, and still within the carrying capacity of the (pond – major) production system. However, only two major commodities- stripped catfish and shrimps – constitutes more than 50% of the national production and are often produced at a high intensity (200-400 tons per ha per year). This intensification does not help improving land use or resources use, rather leads to high discharge of waste into the open waters causing environmental impact, nutrients and economic loss. The aim of the paper is to propose theoretical framework of 3Rs principle – reduce, recycle and reuse – in aquaculture to see the feasibility of transforming current practice to a climate smart aquaculture in the lower Mekong delta of Vietnam. Managing nutrients at system (pond) level allows to produce same amount of fish with 30% less (reduce) feed input where waste nutrients are reused by the food web of the pond and contribute to fish production. This is a zero to lower discharge practice, and thus impact on open water is less. In such an approach nitrogen cycle of the aquatic system functions better and thus emission of N₂O – a component of GHG gas is much lower. Still there remains waste at the bottom which currently used as fertilizer, though not suitable due to high concentration of N and P, and also adds less economic value. Bio-conversion (recycling) of sludge nutrient into animal protein (BSF larvae, earth warm etc.) as feed ingredient (reuse) and further use of bio-conversion waste (as major concentration of N is built in the biomass of the larvae or warm, the waste nutrient composition becomes more suitable for crop as organic fertilizer) as fertilizer can enhance efficiency, sustainability and increase economic gain. 

Keywords: Pond aquaculture, reduce, recycle, reduce, climate smart