Parametric and Optimization Studies on the entrapment of Potassium Fertilizer into Chitosan-Poly(methacrylic acid) Carrier via Ionic Gelation

Nanofertilizer is an emerging technology for exhibiting slow release mechanism of fertilizer application. This slow release mechanism allows increase in nutrient uptake of plants while minimizing environmental pollution; specifically, reducing eutrophication in bodies of water. This study includes parametric and optimization studies for ionic gelation process in the formulation of potassium fertilizer in chitosan polymethacrylic acid (CS-PMAA) carrier, and subsequent characterization of the formulated K fertilizer. A 2k factorial experimnental design was initially implemented to determine significant factors. Results show that polymerization time inversely affects the K content concentration of the K-CS-PMAA fertilizer due to the swelling behavior of chitosan, while K:CS-PMAA ratio directly affects the K content concentration. Upon numerical optimization, the conditions found to maximize K content of the formulated fertilizer are 3000 ppm K+ corresponding to 1.5:1 ratio of the K loading concentration to CS-PMAA carrier for 30 mins polymerization time. The optimum K content of K-CS-PMAA fertilizer is about 34.98% w/w – less than the 44.27% w/w K content of the fertilizer grade, muriate of potash (MOP). The Dynamic Light Scattering (DLS) and Scanning Electron Microscope (SEM) results of 368.1 nm and 75.4 nm, respectively, indicated that K-CS-PMAA is nanosized. The Fourier Transform Infrared Spectroscopy (FT-IR) results proved the presence of CS-PMAA with deviations at 1483.01 and 1405.07 caused by the vibration in the --COO-anion groups of PMAA indicating the attachment of potassium in the nanoparticle. Furthermore, the fertilizer formulated was proved to exhibit slow release behavior with the value of 83.70% K+ release after 48 hours compared to the 99.43% release of MOP

Alkalinity control in ozonated shrimp pond water

The use of ozone for aquaculture has been shown to be effective, not only for disinfection of pathogenic bacteria and viruses, but also for removal of toxic ammonia, nitrite and hydrogen sulfide. However, ozonation of shrimp pond water has a tendency to decrease alkalinity, thereby causing extreme pH fluctuations and affecting the buffering capacity of the pond water. Since the maintenance of alkalinity at optimum levels is very important for shrimp culture, basic research to find suitable strategies to maintain a desired level of alkalinity studies were conducted by ozonating artificial seawater containing ammonia. In the ozonation experiments, pH, alkalinity and total ammonia were monitored. Alkalinity decreased while ammonia was oxidized by oxidants (hypobromous acid) at the rate of 4.2 ppm alkalinity per 1 ppm NH3-N at pH 8.3. The decreasing trend in pH was also observed during ozonation. Different types of liming materials (agricultural lime, marble dust, and coral sand) were evaluated as alkalinity supplements. However, they were found to be ineffective due to their low solubility. Commercial agricultural lime was found to increase alkalinity by recarbonation using diluted CO2 gas. Other more soluble liming materials, such as sodium bicarbonate (SB) and hydrated lime (HL) were tested as possible alkalinity supplements. Sodium bicarbonate (from Australia and China) A-SB and C-SB, and hydrated lime (commercial and from sugar mill, Philippines) c-HL and s-HL were found to increase alkalinity at the rate of 0.6, 0.6, 0.16 and 0.9 mg/L per 1 ppm liming material, respectively. The pH of the ozonated water with 40 ppm sodium bicarbonate was more stable compared to that with 40 ppm hydrated lime. This implies that with sodium bicarbonate, alkalinity and pH of ozonated pond water can easily be maintained at optimum levels. Hence, the use of ozonation for oxidation, mixing and disinfection, coupled with proper alkalinity control can bring about the maintenance of good water quality for prawn cultivation

Carbon Storage of Leyte Sab-A Basin Peatland, Philippines

Leyte Sab-A Basin peatland (LSBP) is the second largest peatland in the Philippines and comprises 3,088 ha (31 km2). The study estimated the C storage and carbon sequestration capacity of the peatland’s four (4) ecotypes, namely, swamp forest (SF), marshland (ML), agroforestry (AF), and agricultural land (AL) using allometric equations. SF rendered the highest downed wood C-stocks followed by AL and AF. For the litter C-stocks, AF rendered the highest, followed by SF, ML, and AL. SF rendered the highest root C-stocks and CO2 sequestered, followed by AL and AF. C% is highest in ML with values ranging from 32-43 C% across the soil peat depth, while SF ranges from 29-34 C%, and AL and AF both with 19-37 C%. The LSBP stores 36.6 Tg of C and 134.5 Tg of CO2 sequestered. This C storage amount can represent 0.04% of tropical peat carbon

Assessment of the Effect of Remediation Strategies on the Environmental Quality of Aquaculture Ponds in Marilao and Meycauayan, Bulacan, Philippines

Background. Water quality in the Marilao-Meycauayan-Obando river system (MMORS) of Bulacan, the Philippines, is of great concern due to the pollution load from local industries. The river system is currently used as a source of water for the aquaculture industry in Bulacan. Objectives. In order to address organic and heavy metal pollution, several remediation strategies were tested in aquaculture ponds along the river system. Strategies such as phytoremediation (vetiver grass pontoons), application of probiotics and zeolite (with filtration as pre-treatment) were utilized in ponds to decrease or remove toxic pollutants in water and sediments. Methods. Two sites were chosen as the pilot remediation sites – ponds in Barangay Nagbalon, Marilao and Barangay Liputan, Meycauayan, Bulacan. Pond bottom preparation was done to improve the condition of the pond bottom sediments before stocking by adding zeolite. Physicochemical parameters of water such as dissolved oxygen (DO), temperature, pH, salinity, ammonia, phosphate, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were monitored throughout the culture period. Heavy metals in sediments and fish were monitored. Fish parameters such as average body weight and feed conversion ratio were determined. Results. The DO levels were below recommended levels in the morning and reached a supersaturated level in the afternoon. Ammonia and COD levels were above recommended limits. A decreasing trend was observed for ammonia levels in treatment ponds. In terms of the growth of milkfish, the pond with probiotics showed the highest growth and better feed conversion ratio in Nagbalon and in the phytoremediation pond in Liputan. Percentage survival of milkfish was much higher at Liputan. Copper, chromium, lead and manganese were detected in pond sediments. After application of zeolite, there was a decrease in lead levels throughout the culture period. Conclusions. The different remediation studies were compared in terms of cost, effectivity and application and phytoremediation (vetiver grass pontoons) was determined to be the most cost-effective remediation strategy. Competing Interests. The authors declare no competing financial interests

Size reduction of taro (Colocasia esculenta L. Schott) starch through sonification and nano precipitation

Starch nanoparticles have been gaining research interest for its potential to improve mechanical and barrier properties of biocomposites and carrying capacity for active ingredients. Taro is one of the indigenous tubers in the Philippines that is a good candidate for generating starch nanoparticles since it has lower granule size as compared to other starchy tubers. This study aims to optimize the generation of taro starch with reduced particle size through ultrasonication and nano precipitation. Central composite design of the response surface methodology was used to determine the optimum condition (starch concentration (%w/v), sonication time (min), and starch:ethanol ratio (v/v)) to reduce the size of taro starch based on the Z-average of particles. The model generated was used to predict an optimum run to produce the taro starch with the lowest Z-average. Starch:ethanol ratio was found to have significant linear and quadratic effects on the model. After validation, the optimum run produced a taro starch with Z-average of 256.74±14.75 nm with 0.65% error. The size cannot be considered as a nanoparticle based on ISO standard. Using the equation generated from the model, parameters like sonication time can be set to minimum and starch concentration can be set to maximum to produced the highest yield at the shortest processing time. This study focused on the optimization and characterization of laboratory scale produced taro starch with reduced particle size and did not include pilot commercial run

Parametric and Optimization Studies on the entrapment of Potassium Fertilizer into Chitosan-Poly(methacrylic acid) Carrier via Ionic Gelation

Nanofertilizer is an emerging technology for exhibiting slow release mechanism of fertilizer application. This slow release mechanism allows increase in nutrient uptake of plants while minimizing environmental pollution; specifically, reducing eutrophication in bodies of water. This study includes parametric and optimization studies for ionic gelation process in the formulation of potassium fertilizer in chitosan polymethacrylic acid (CS-PMAA) carrier, and subsequent characterization of the formulated K fertilizer. A 2k factorial experimnental design was initially implemented to determine significant factors. Results show that polymerization time inversely affects the K content concentration of the K-CS-PMAA fertilizer due to the swelling behavior of chitosan, while K:CS-PMAA ratio directly affects the K content concentration. Upon numerical optimization, the conditions found to maximize K content of the formulated fertilizer are 3000 ppm K+ corresponding to 1.5:1 ratio of the K loading concentration to CS-PMAA carrier for 30 mins polymerization time. The optimum K content of K-CS-PMAA fertilizer is about 34.98% w/w – less than the 44.27% w/w K content of the fertilizer grade, muriate of potash (MOP). The Dynamic Light Scattering (DLS) and Scanning Electron Microscope (SEM) results of 368.1 nm and 75.4 nm, respectively, indicated that K-CS-PMAA is nanosized. The Fourier Transform Infrared Spectroscopy (FT-IR) results proved the presence of CS-PMAA with deviations at 1483.01 and 1405.07 caused by the vibration in the --COO-anion groups of PMAA indicating the attachment of potassium in the nanoparticle. Furthermore, the fertilizer formulated was proved to exhibit slow release behavior with the value of 83.70% K+ release after 48 hours compared to the 99.43% release of MOP

Microwave-Assisted Extraction of Pectin from “Saba” Banana Peel Waste: Optimization, Characterization, and Rheology Study

One way to valorize “Saba” banana peel waste is to extract high-value compounds, such as pectin, and use it for food applications. In this study, the parameters for the microwave-assisted extraction of pectin were screened and optimized using Response Surface Methodology. The pectin was purified and then subjected to characterization. Results showed that the optimum extraction conditions were 195°C, 8% solid-liquid ratio, and pH 3 hydrochloric acid (HCl), with predicted and actual yields of 12.8% and 14.2%, respectively. The subsequent purification method increased the purity of pectin by 300%. The pectin was found to be low-methoxy in nature and had an average particle size of 300 nm. The pectin application in whey protein isolate resulted in a shear-thinning fluid, with an improved viscosity compared to a control. When applied to a commercial orange juice, the in vitro digestion study showed that the fluid’s viscosity was higher before and during the gastric and intestinal digestion at the low physiological shear rate

DNA-based electrochemical nanobiosensor for the detection of Phytophthora palmivora (Butler) Butler, causing black pod rot in cacao (Theobroma cacao L.) pods

© 2019 Elsevier Ltd A nanobiosensor was developed for the electrochemical detection of Phytophthora palmivora, a notorious pathogen of cacao causing severe crop loss. Sandwich hybrids between two oligonucleotide probes and the genomic DNA of P. palmivora were prepared and electrochemically detected. The oligonucleotide probes were designed based on the ITS sequence of the P. palmivora field isolates. The detection of sandwich hybrids with P. palmivora genomic DNA and the selectivity of the nanobiosensor towards it compared to other cacao-associated fungal pathogens were demonstrated. The detection limit was determined to be at 0.30 ng DNA μL−1. Detection of P. palmivora DNA on cacao samples was also demonstrated. The result of the preliminary analysis on cacao pod samples shows the potential of the developed nanobiosensor for reliable and more cost-effective analysis of field samples

Prevalence of yellow head virus in cultured black tiger shrimp (Penaeus monodon Fabricius) from selected shrimp farms in the Philippines

The prevalence and geographic distribution of Yellow head virus (YHV) in cultured Penaeus monodon in the Philippines was documented by Western blot assay. Fifty-three out of 219 samples (24.2%) were found to be positive for YHV infection. Among the ten provincial sampling sites, selected shrimp farms from Misamis Occidental had the highest prevalence of infection with 66.7% followed by South Cotabato, Negros Occidental and Capiz with 43.7%, 35.4% and 33.3% respectively. Selected shrimp farms in Agusan del Norte and Bohol were also positive for YHV infection at lower prevalence. Samples from Bataan, Batangas, Cebu and Misamis Oriental were all negative for YHV infection. The prevalence of YHV in the different life stages of shrimp was also determined. Post larval stage had the highest prevalence of infection with 54.5% followed by the juvenile stage with 40.8% and adult stage with 16.9%. Infectivity studies resulted to 60% cumulative mortality 17 days post-infection in juvenile shrimp and 50% cumulative mortality 19 days postinfection in adult shrimp. YHV infection was further confirmed by electron microscopical examination, histopathological examination and in vitro infectivity assay