The enrichment of diet with beneficial bacteria (single- or multi- strain) in biofloc system enhanced the water quality, growth performance, immune responses, and disease resistance of Nile tilapia (Oreochromis niloticus)

The increased dependence of farmers on chemical fertilizers poses a risk to soil fertility and ecosystem stability. Plant growth‐promoting rhizobacteria (PGPR) are at the forefront of sustainable agriculture, providing multiple benefits for the enhancement of crop production and soil health. Bacillus subtilis is a common PGPR in soil that plays a key role in conferring biotic and abiotic stress tolerance to plants by induced systemic resistance (ISR), biofilm formation and lipopeptide production. As a part of bioremediating technologies, Bacillus spp. can purify metal contaminated soil. It acts as a potent denitrifying agent in agroecosystems while improving the carbon sequestration process when applied in a regulated concentration. Although it harbours several antibiotic resistance genes (ARGs), it can reduce the horizontal transfer of ARGs during manure composting by modifying the genetic makeup of existing microbiota. In some instances, it affects the beneficial microbes of the rhizosphere. External inoculation of B. subtilis has both positive and negative impacts on the endophytic and semi‐synthetic microbial community. Soil texture, type, pH and bacterial concentration play a crucial role in the regulation of all these processes. Soil amendments and microbial consortia of Bacillus produced by microbial engineering could be used to lessen the negative effect on soil microbial diversity. The complex plant–microbe interactions could be decoded using transcriptomics, proteomics, metabolomics and epigenomics strategies which would be beneficial for both crop productivity and the well‐being of soil microbiota. Bacillus subtilis has more positive attributes similar to the character of Dr. Jekyll and some negative attributes on plant growth, soil health and the environment akin to the character of Mr. Hyde.

Bacillus subtilis impact on plant growth, soil health and environment: Dr. Jekyll and Mr. Hyde

The co-culture of microalgae and specific bacteria is conducive for improving wastewater treatment efficiency. In this study, native bacterial strains isolated from pig biogas slurry were screened for effective biogas slurry treatment when co-cultured with different microalgae. Scenedesmus obliquus and Bacillus megaterium (So-B) co-culture was found more efficient in treating high concentration biogas slurry compared with the pure microalgae culture. When the C/N/P ratio in biogas slurry was 106/16/1 and the initial microalgae-bacteria inoculation ratio was 9:1, the co-culture attained the maximum chemical oxygen demand (COD), total phosphorus (TP) and ammonia nitrogen (NH4+-N) removal rates of 85.98 %, 81.03 % and 65.48 %, respectively. High C/N ratio was favorable for NH4+-N removal by the co-culture. In addition, co-culture with bacteria markedly increased the ratio of saturated/unsaturated fatty acids in microalgae. These results suggest that the co-culture could efficiently reduce various nutrients in biogas slurry and simultaneously accumulate biomass with higher biofuel characteristics.

Co-culture of bacteria and microalgae for treatment of high concentration biogas slurry

Recent advances in Shrimp aquaculture wastewater management.

Shellfish processing is vital for the extraction of crustacean meat in the seafood market. Their processing results in shellfish wastes containing high-value products like chitin. The common method for chitin recovery practised globally utilizes harsh chemicals like HCl and NaOH, for the demineralization and deproteination of the shellfish wastes, releasing harmful acidic and basic effluents as flow through. Recently, mathematical and computational tools are employed to monitor and regulate the concentration of chemical effluents being released from the chitin/chitosan industries. As an alternate measure to prevent the disposal of effluents, greener remediation measures have been preferred for the recovery of chitin. The current paper discusses the harmful effects of the wastes generated by seafood processing and chitin/chitosan industries by chemical methods and suggests a guideline on alternate green environmentally friendly methods like microbial fermentation, application of enzymes, Natural Deep Eutectic Solvents (NADES) etc. for the production of high-quality chitin and other chemical-free protein hydrolysates and their bioprospecting.

Green remediation of the potential hazardous shellfish wastes generated from the processing industries and their bioprospecting

The use of Bacillus species in maintenance of water quality in aquaculture: A review

Prevalence of virulence genes and antibiotic susceptibility of Bacillus used in commercial aquaculture probiotics in China

Aims: This study analyses the economic performance and gender distribution of the small-scale aquaculture of Ghana using Net Present Value (NPV), Internal Rate of Return (IRR), Cash flow as well as gender distribution of the small-scale aquaculture of Ghana.  
Study Design: This study is exploratory in its design. The study identified certain relationships and associations. Data was gathered from a sample drawn from a population.  Questionnaire-based interview was designed and administered to the small scale fish farmers in the Sunyani metropolis. Both quantitative and qualitative research methods will be employed for the study. A case study method will also be used due to the fact that it has the benefit of permitting for an intensive collection of data required to fulfil the goals of the research 
Place and Duration of Study: The study was conducted at the Sunyani Municipality in the Brong Ahafo Region of the Republic of Ghana between November 2017 and February 2018. 
Methodology: The study randomly selected 20 farms out 40 farms and farmers interviewed using questionnaire. A 600 m2 pond was further selected as a model of the small-scale aquaculture and used to perform the economic analysis. 
Results: The total start-up capital for a 600-meter square pond is estimated at $2693.15. Huge part, 56.9 percent, of the amount goes into fixed investment like pond construction, acquisition of land, and farm buildings. The economic analysis shows a viable industry with an estimated NPV of $605.4484 and IRR of 24.19 percent.    
With gender, the study reveals a huge gap in man-woman distribution in the fish farming trade. Majority of the farms surveyed did not females, with the male having 77 against the female with 23%. 
Conclusion: The study has found a viable aquaculture industry with high profitability that can improve the livelihood of fish farming households.

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Economic Analysis of Small-Scale Aquaculture Enterprise in Ghana; a Case Study of Sunyani Municipality

Offshore industries and resources are the links between humans and the marine ecosystem. Several risk factors are associated with beach activities. The risk of Vibrio infection at bathing beaches is often overlooked as there are virtually no regulations regarding them. In this study, we investigated the current prevalence of pathogenic Vibrio spp. on the main beaches of Shenzhen. The risk indicator levels of pathogenic Vibrio species obtained were analyzed using 17 virulence genes mainly associated with Vibrio species and are responsible for several ailments and infections. A total of 60 Vibrio strains were isolated and identified by morphological observation, evolutionary tree alignment, and biochemical testing. There was a high abundance of Vibrio in the seawater. Also, a positive correlation was observed between the presence of virulence genes and the exhibition of high pathogenicity after artificially infecting fish with some of the virulent Vibrio species. In the infection experiment, it was observed that all the zebrafish infected with MEDF7 (Vibrio alginolyticus) and JSW-YELLOW (Vibrio harveyi) died a day after injection, with varying degrees of abdominal enlargement and skin ulceration. The mortality rates for strains with medium risk and low risk were 65% and 45%, respectively. Lethal dose 50 (LD50) values were 5.67 ×104 CFU/fish, 3.72 ×105 CFU/fish, and 4.31 ×105 CFU/fish for the high-risk, medium-risk, and low-risk strains of zebrafish, respectively. The results of the antibiotic sensitivity test showed that all the six experimental strains, except JSW-YELLOW, were resistant to doxycycline and neopenicillin. In summary, our study first identified and evaluated the pathogenicity of Vibrio in the Shenzhen beach baths, serving as a scientific benchmark for Vibrio risk prevention and control as well as guidance for Vibrio diagnosis through virulence factor detection and risk classification.

Melody Abena Anokyewaa

Papers

The use of Bacillus species in maintenance of water quality in aquaculture: A review

Prevalence of virulence genes and antibiotic susceptibility of Bacillus used in commercial aquaculture probiotics in China

Economic Analysis of Small-Scale Aquaculture Enterprise in Ghana; a Case Study of Sunyani Municipality

Pathogenicity and antibiotic resistance analysis of Vibrio species found in coastal water at mainly beach of Shenzhen, China