It was reported that the extracts of papaya leaves could inhibit the growth of Rhizopus stolonifer. Antibacterial activity of Carica papaya leaf extracts on pathogenic bacteria was observed in this study. Papaya leaves were extracted by using maceration method and three kinds of solvents: ethanol, ethyl acetate, and hexane. Papaya leaf extracts were tested against Bacillus stearothermophilus, Listeria monocytogenes, Pseudomonas sp., and Escherichia coli by agar diffusion method. The objectives of this study were to determine extract ability against pathogenic bacteria, to observe the influence of pH, NaCl, and heat on extracts ability, and to observe extract ability against B. stearothermophilus spores. The data showed that ethyl acetate extract could inhibit B. stearothermophilus, L. monocytogenes, Pseudomonas sp., and E. coli. The extract activity was influenced by pH, and it was more effective in low pH. The extract activity was influenced by NaCl against B. stearothermophillus and E. coli. However, it was not influenced by NaCl in bioassay against L. monocytogenes and Pseudomonas sp. The extract activity was influenced by heating process against all the bacteria tested. The extracts inhibited B. stearothermophilus spores as well. Papaya leaves are potential natural antibacteria, which might be used in certain kinds of food.

Abstract. Irawati W, Parhusip Ajn, Christian S, Yuwono T. 2017. The potential capability of bacteria and yeast strains isolated from Rungkut Industrial Sewage in Indonesia as a bioaccumulators and biosorbents of copper. . Heavy metal pollution is a serious problem as a result of industrialization due to the high production of wastewaters containing high concentrations of heavy metals. Wastewater contains microbial populations adapted to the toxic concentrations of heavy metals and becomes resistant by accumulating copper inside the cells. The aims of the study were to isolate yeast and bacteria from Rungkut Industrial sewage in Indonesia, and to examine the capability of these isolates to accumulate and biosorb copper. The copper resistance was determined by measuring minimum inhibitory concentration (MIC). The capability of isolates to accumulate and biosorb copper were determined by atomic absorption spectrophotometer. Biosorption is described as how much copper is removed from a growth medium with reference to the initial concentration. Of this study, nine bacterial strains and eight yeast strains were obtained with the MICs of 6-7 mM, and 16-20 mM CuSO 4 , respectively. Afterward, we have successfully selected three bacteria and one yeast strains showing the highest copper resistance. The three bacterial strains, designated as C1, C2, and C4 were able to accumulate copper up to 29.93, 508.01, 371.42 mg/cell dry weight, respectively. While the yeast strain, ES9.3 was able to accumulate 0.52 mg/cell dry weight and reduce up to 82.32% copper concentration in the medium. The findings of this study indicated that yeast and bacterial strains were promising microorganisms for removal of copper.

Phytoremediation is a bioremediation process using plants and microorganisms to extract, sequester, or detoxify heavy metals. Eichhornia crassipes [(Mart.) Solms] is a well-known phytoremediating plant that has the ability to remove heavy metals from water by accumulating them in their tissues. Acinetobacter sp. IrC1 and Acinetobacter sp. IrC2 are copper resistant bacteria isolated from industrial waste in Rungkut, Surabaya. The aim of this research was to study the effect of Acinetobacter sp. IrC1 and Acinetobacter sp. IrC2 inoculation in copper phytoremediation process using Eichhornia crassipes. Bacterial isolate with colony form unit of 10 8 was inoculated into the rhizosphere of Eichhornia crassipes in water containing 10 mL · L −1 and 20 mL · L

Melinjo (Gnetum gnemon L.) is an Indonesian native plant which has not been widely accepted due to its limited utilization. Mainly, melinjo is consumed as an ingredient to make a vegetable dish or as raw material of ‘emping’. The purpose of this research was to study the antimicrobial activity of the melinjo seed extract and melinjo peel extract. In this study, extraction from melinjo seed and peel was conducted by maceration using three kinds of solvent: ethanol, ethyl acetate and hexane for 24 h at room temperature. The results showed that none of the melinjo extracts (concentration from 5% - 25% w/v) could inhibit the growth of Aspergillus flavus IPBCC 88.030; whereas for Bacillus cereus ATCC 10876, Staphylococcus aureus ATCC 25953, and Enterobacter aerogenes ATCC 13048 there was efficient inhibition by 5% (w/v) of melinjo seed-ethanol extract. The minimal inhibitory concentration (MIC) value of melinjo extract was ranged from 0.26 μg mL-1 to 1.46 μg mL-1, whilst the minimal bactericidal concentration (MBC) value was ranged from 1.02 μg mL-1 to 6.04 μg mL-1. The inhibitory capacity of extract had a similar level as compared to 10 ppm penicillin G on B. cereus ATCC 10876 as well as on S. aureus ATCC 25953. Furthermore, as compared to 10 ppm streptomycin, the inhibitory capacity of the extract was equal for the all tested bacteria. Cell wall deformation was observed using SEM, and confirmed by the presence of ions (Ca2+ and K+) outside of the cells, detected by means of AAS

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