Rodhiansyah Djayasinga

This study reports the first isolation of an Enterobacter cloacae complex (ECC) strain, closely related to Enterobacter hormaechei (99.86% 16S rRNA identity), associated with bacterial blight symptoms in rice in Lampung, Indonesia. Acknowledging 16S rRNA limitations within ECC, species identification is reported cautiously, while pathogenicity profile fulfilled Modified Koch's Postulates. To address chemical bactericide limitations, we developed sustainable multiphase nanoparticles from chicken eggshell waste through mechanical and thermal decomposition approaches. The produced nanoparticles were characterized using XRD, TEM, FTIR, SEM-EDS, PSA, and UV-DRS. The results showed that the nanoparticles consisting of Ca(OH)2, CaO, and β-tricalcium phosphate, with a dimension of 11–31 nm (XRD) and 20–23 nm (TEM). The FT-IR/EDS data confirmed OH⁻, Ca, O, and P elements, while UV-DRS showed a bandgap energy of 5.96 eV. Descriptive statistical analysis (n=6) evaluated antibacterial activity via disk diffusion (20 µg/disk) against the ECC isolate, compared to ampicillin sulbactam (SAM 20). Nanoparticles yielded a mean inhibition zone of 10.06±0.02 mm for responsive replicates, demonstrating moderate activity. Within the zones, bacterial cells showed morphological damage, likely caused by Ca²⁺ and OH⁻ release, inducing membrane disruption and oxidative stress. Furthermore, spatially graded element distribution (Ca, O, P) and β-TCP as a controlled release matrix support sustained bioactivity. These findings reveal eggshell-derived nanoparticles as a promising, economical, and environmentally friendly antibacterial agent for sustainable rice disease management.

Chicken eggshell waste, though abundant in CaCO3 that can be converted into various products like calcium hydroxide nanoparticles (NPs), has received limited attention. This study aimed to synthesize calcium hydroxide NPs from eggshell waste and evaluate their antibacterial properties against Staphylococcus aureus and Escherichia coli. The researchers employed a top-down approach with thermal decomposition to produce environmental-friendly calcium hydroxide NPs, and conducted in vitro tests to assess their antibacterial activity, with and without exposure to sunlight. The minimum inhibitory concentration and disc diffusion methods were used to evaluate the antibacterial effects. X-Ray diffraction analysis confirmed the synthesis of calcium hydroxide NPs. Further, a paired T-test showed that the calcium hydroxide NPs exhibited significant antibacterial activity against both bacterial through photocatalytic mechanisms, in comparison to their performance without such techniques. The utilization of green synthesis techniques to produce materials with potential antimicrobial applications presents significant developmental opportunities for the future.

The research was conducted in June-September 2022. The early breastfeeding initiation rate (EBI) in one of the districts in Indonesia in 2022 will only reach 8.74%, of the target of 42%. This study aimed to increase the percentage of EBI implementation in birthing mothers and the success of EBI in the first 30 minutes of labor through the development of EBI model. The research method uses a quasi-experimental control group design. The population is 96 people. The sample is the total population, consisting of 48 people closest to pregnant women plus 48 people in the control group. The effect of mentoring shows significant results on the success of EBI because of the value of p=0.002. The mother's educational contribution did not affect the success of EBI between the intervention group and the control group (p=0.774). The family support factor resulted in a significant EBI win between the intervention and control groups (p=0.000). The achievement of EBI provision was 100% of the target of 60%, the achievement of EBI>1 hour was 7.2%, and EBI<1 hour was 92.8%.

Identifying the most effective material with antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is a challenging task considering the rising concerns about drug resistance. Various experiments through in vitro and in vivo studies to obtain antibacterial agents using abundant and easily available raw material sources have been conducted. Therefore, this study aimed to acquire semiconducting nanoparticle material derived from purebred chicken eggshell waste that could effectively function as an antibacterial agent. The waste treatment was carried out using a top-down method applying the thermal decomposition method with calcination temperatures of 700 and 800 ºC for 30 hours. XRD analysis results showed CaO as a major phase and this was further supported by Rietveld calculation. The size of the crystalline phases obtained ranged from 10–45 nm, while FTIR analysis showed the appearance of CaO bond at a wave number of 715.65 cm-1. Furthermore, SEM analysis showed a rough folded particle surface with a pore percentage of 48.20%. Based on the UV-Vis DRS analysis results, chicken eggshell powder had band gap energy characteristics of 2.07, 2.74, 3.71, and 5.96 eV for sample B, as well as 4.60 and 5.82 eV for sample C. Activation of purebred chicken eggshell powder as antibacterial was performed both qualitatively and quantitatively using photocatalytic and non-photocatalytic methods. Qualitatively, both samples showed antibacterial activity, with a minimal inhibitory concentration (MIC) of 1,000 µg/mL.

Media Plate Count Agar (PCA) merupakan media pertumbuhan bakteri yang biasanya digunakan untuk pemeriksaan kualitas bahan makanan. Berdasarkan observasi yang dilakukan penulis pada September 2020 di Laboratorium Bakteriologi Jurusan Analis Kesehatan, media pertumbuhan bakteri dalam bentuk fisik yang baik disimpan dalam lemari pendingin bersuhu 2-8oC selama ±1-2 minggu, media pertumbuhan bakteri dipanaskan saat akan digunakan untuk praktikum. Pemanasan berulang dapat menurunkan pH media dan menyebabkan koloni bakteri yang tumbuh semakin sedikit. Tujuan penelitian ini adalah mengetahui pengaruh pemanasan media PCA 1x, 2x, 3x, dan 4x terhadap pH dan jumlah koloni bakteri. Jenis penelitian eksperimen dengan desain penelitian Rancangan Acak Lengkap dan dianalisis menggunakan ANOVA kemudian dilanjutkan dengan Uji BNT. Hasil rerata pH media PCA setelah dilakukan pemanasan 1x adalah 6.82, pemanasan 2x adalah 6.70, pemanasan 3x adalah 6.54, dan pemanasan 4x adalah 6.36. Rerata jumlah koloni bakteri media PCA pemanasan 1x adalah 5,28 x 102 koloni/ml, pemanasan 2x adalah 2,66 x 102 koloni/ml, pemanasan 3x adalah 1,18 x 102 koloni/ml, dan pemanasan 4x adalah 3,9 x 101 koloni/ml.

Chicken eggshell waste is a promising source of CaO which can be converted into heterogeneous catalyst materials. The purpose of this study was to utilize CaO heterogeneous catalyst derived from breed chicken eggshell to produce biodiesel from waste cooking oil through the transesterification process. A total of 4 g of catalyst material was mixed with 200 g of waste cooking oil and 60 g of methanol, and then the mixture was stirred at a speed of 700 rpm for 6 h at 60 ± 40C. The produced biodiesel was analyzed using GC-MS to elucidate the various methyl ester compounds. The produced biodiesel was found to have a density of 855 kg/m3, viscosity of 3.74 mm2/s (cSt), and flash point of 135 0C. Based on these results, it can be concluded that breed chicken eggshells are potential sources for the preparation of CaO catalyst material to produce biodiesel from waste cooking oil. This finding is very useful for further optimization of mass catalysts heterogeneous CaO from breed chicken eggshells including the commercial production of biodiesel.