Pertumbuhan bakteri jerawat dapat diatasi dengan menggunakan senyawa antibakteri, tanaman yang berpotensi untuk dikembangkan sebagai antibakteri jerawat adalah Citrus x microcarpa Bunge (jeruk kunci). Berdasarkan  kajian  literatur, genus Citrus mengandung steroid, flavonoid, terpenoid, tanin, dan saponin dengan bioaktivitas sebagai antioksidan dan antibakteri. Penelitian ini bertujuan untuk mengetahui kandungan metabolit sekunder dan aktivitas antibakteri ekstrak limbah buah jeruk kunci terhadap Propionibacterium acnes. Pada penelitian ini ekstraksi menggunakan metode maserasi dengan pelarut etanol. Pengujian fitokimia dilakukan secara kualitatif dan uji antibakteri menggunakan metode difusi cakram. Hasil pengujian fitokimia mengandung senyawa metabolit sekunder, seperti flavonoid, tanin, terpenoid, dan steroid. Berdasarkan data pengujian antibakteri ekstrak limbah buah jeruk kunci didapatkan bahwa kekuatan  antibakteri ekstrak terhadap P. acnes tergolong kuat. Hal tersebut dapat disimpulkan bahwa ekstrak limbah buah jeruk kunci berpotensi untuk dikembangkan menjadi agen antibakteri.

Antibacterial tests were carried out using ethanol extract of kelubi meat (Eleidoxa conferta), extraction using the Microwave-Assisted Extraction method with a ratio of 2: 20 for 30 minutes at 60 °C. Antibacterial tests using diffusion methods with concentrations of 20%, 40%, 60%, 80%, and 100%; positive control of 0.005% amoxillin and DMSO negative control. Antibacterial test results showed that the inhibition zone of ethanol extract in E. coli bacteria with a concentration of 20% was in the moderate category, for a concentration of 40% including the strong category while the concentration of 60%, 80% and 100% was very strong. The inhibition zone of ethanol extract for the S. aureus bacterium with a concentration of 20% is included in the strong category while the concentration of 40%, 60%, 80%, and 100% is categorized as very strong. From these results it can be concluded that the inhibitory zone in Stapylococcus aureus bacteria is greater than that of E. coli bacteria.

Antibacterial tests were carried out using ethanol extract of kelubi meat (Eleidoxa conferta), extraction using the Microwave-Assisted Extraction method with a ratio of 2: 20 for 30 minutes at 60 °C. Antibacterial tests using diffusion methods with concentrations of 20%, 40%, 60%, 80%, and 100%; positive control of 0.005% amoxillin and DMSO negative control. Antibacterial test results showed that the inhibition zone of ethanol extract in E. coli bacteria with a concentration of 20% was in the moderate category, for a concentration of 40% including the strong category while the concentration of 60%, 80% and 100% was very strong. The inhibition zone of ethanol extract for the S. aureus bacterium with a concentration of 20% is included in the strong category while the concentration of 40%, 60%, 80%, and 100% is categorized as very strong. From these results it can be concluded that the inhibitory zone in Stapylococcus aureus bacteria is greater than that of E. coli bacteria.

The Growth of Horticultural Crops on Ex-Tin Mined Soil, Bangka. Growth evaluation of the plant parts consumed from various horticultural species is needed in an effort to determine adaptive economic plant species in ex-tin mined soil. This study aims to determine the growth of crops on ex-tin mined soil and on undisturbed soil in Bangka regency. Three individuals of each species were then measured for their root dry weight, horizontal root length, vertical root length, plant height, stem diameter, canopy width, shoot dry weight, and leaf thickness and leaf area. Plant growth on control land was higher than the growth on ex-tin mined soil for most of the parameters. It is suspected that this is due to the physical, chemical and biotic properties ex-tin mined soil properties which are not yet optimal for growth.