No abstract

Rice husks are often dumped and burned in the field that emits greenhouse gases. Through green nanotechnology, developing these materials into diverse applications will not only create an avenue for new ideas and innovations but also beneficial to the environment. Thus, this study aimed to utilize rice husks in an eco-friendly way. Rice husks were converted into rice husk biochar (RHB) through continuous-type rice husk pyrolizer (CtRHP) which produces two important products: heat energy and biochar. High grade RHB was used as an amendment for degraded acid upland soil (Annam series) grown with corn. Plant height and biomass, and total N uptake, increased linearly with increasing rates of RHB levels. A linear trend of the effects of RHB on soil pH (water), and total N with the increasing RHB rates while soil pH and OC had a quadratic trend. The produced RHB were further derivatized into nanosilica (nSi). Characterization of nSi through SEM micrographs showed a cloudy-like structure with various particle sizes ranging from 5 to 20 nm, while XRD analysis revealed that the synthesized nSi is amorphous. Converting RHB into nSi will have various industrial applications such as catalysts, electronic and thin film substrates, and humidity sensors.

Garlic contains various polyphenolic compounds such as anthocyanin, a bioactive, water-soluble compound generally known for its remarkable health-enhancing properties. However, it is chemically unstable and easily degrades due to various environmental conditions (temperature, pH, presence of oxygen and light, etc.) in addition to its low bioavailability due to fast metabolization and low absorption in the body. Therefore, a nanoencapsulation strategy is essential to address these limitations. In this work, anthocyanin extraction from FBG (Ilocos variety) with 85% acidified ethanol and its encapsulation using the chitosan-alginate nanoparticle system via pre-gelation and polyelectrolyte complex formation were demonstrated. Anthocyanin-loaded chitosan-alginate nanocapsules were characterized in terms of structural features, particle size, morphology, encapsulation efficiency, total phenolic content (TPC), and radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The obtained anthocyanin-loaded nanocapsules have small particle sizes ranging from 50.7 nm to 92.0 nm with high encapsulation efficiency (T3: 78.82%, T2: 68.18%, T1: 65.77%). Results showed that a higher initial concentration of anthocyanin extract promotes higher encapsulation efficiency. Antioxidant activity of the nanocapsules showed low phenolic content (0.11 mg GAE/g) but high DPPH scavenging activity (14.02 mg AAE/g). The chitosan-alginate complex has successfully encapsulated the anthocyanin from fermented black garlic.

Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio species is one of the most common bacterial diseases carrying the plasmid encoding pirA vp and pirB vp toxin genes that cause lethargic and anorexic effect on infected shrimps due to induced necrosis in the hepatopancreas. This study demonstrates the use of gold nanoparticles (AuNPs) coupled with specific thiol probe for the detection of pirA vp toxin gene causing AHPND. Detection of pirA vp toxin gene using thiol probe was validated using colorimetric assay. The validation results showed that the developed Deoxyribonucleic acid (DNA)-based AuNPs detection was specific and highly sensitive to detect the pirA vp toxin gene at 20 fg/ul of shrimp genomic DNA. This nanotech-based polymerase chain reaction (PCR) amplification-free protocol can serve as a new means of diagnostic strategy for AHPND detection in aquaculture industry. Furthermore, the method provides accurate and timely detection on field setting which can help to reduce mass mortality and drastic economic losses on aquaculture.

Abstract. Zinc oxide nanoparticles (ZnO NPs) are known to be one of the multifunctional inorganic nanoparticles with its application in the treatment of bacterial pathogens, especially when synthesized through green nanotechnology. In this study, ZnO NPs were successfully synthesized through co-precipitation method and its antibacterial activity against Ralstonia solanacearum was evaluated. Surface morphology through scanning electron microscope (SEM) exhibited an agglomerated rod-like structures, with a mean particle size of 180.9 nm. Phytochemical screening was performed through various chemical qualitative tests, to which the presence of terpenoids and cardiac glycosides in Caesalpinia sappan leaves was confirmed in the aqueous extract. Five treatments were evaluated against R. Solanacearum in terms of their zone of inhibition. The highest zone of inhibition from the different concentrations was observed from the positive control (Gentamicin) with a mean value of 34.47 mm, followed by 0.57 g/mL ZnO NPs with a mean value of 21.69 mm, and no zone of inhibition on the negative control, 0.28 g/mL, and 0.19 g/mL of synthesized ZnO NPs. Antibacterial activity of ZnO using disc diffusion method resulted in a significant zone of inhibition which proves that synthesized nanoparticles can be used as a potent antibacterial agent against R. solanacearum.