Abstract. Wiraswati SM, Nawangsih AA, Rusmana I, Wahyudi AT. 2020. Rice phyllosphere bacteria producing antifungal compounds as biological control agents of blast disease. Biodiversitas 21: 1273-1278. In vitro analysis of rice phyllosphere bacteria can be developed as biocontrol agents of blast disease using their antifungal activity. To prove the efficacy of bacterial isolates in reducing the severity of blast disease, a greenhouse experiment was conducted. Furthermore, antifungal compounds produced by potential bacterial isolate were also identified using Thin Layer Chromatography (TLC) and Liquid Chromatography-Mass Spectrometry/ Mass Spectrometry (LC-MS/MS) analysis. The application of seven rice phyllosphere bacterial isolates significantly reduced the severity of blast disease in rice (var: Ciherang). Surprisingly, the isolate STGG 14 is the most effective with 70.83% of blast disease reduction. Isolate STGG 14 has been identified as Bacillus subtilis subsp. subtilis which is known as various bioactive compounds producer. It was confirmed through identification of antifungal compounds produced by isolate STGG 14. The bioautography test shows that crude bioactive compounds from isolate STGG 14 could inhibit P. oryzae race 173. On the further analysis using LC-MS/MS, four bioactive compounds isolated from isolate STGG 14 were identified as moracin C, psoralen, 4,6-dimethyl-3 (4’-hydroxyphenyl) coumarin and xanthotoxin. All identified compounds except moracin C, belong to the coumarin group. According to the previous studies, among all compounds, psoralen and xanthotoxin displayed antifungal activity against several fungal pathogens.

The abundant volume of coffee bean pulp as a  by-product of the post-harvest processing is an important source of soil organic matter if it is properly handled. The alternative way to use coffee bean pulp waste to reduce the impact of environmental pollution is composting. This study aims to determine the ability of actinomycetes to degrade coffee pulp, to identify the physical and chemical characteristics of coffee pulp compost, and to evaluate the effect of coffee pulp compost on chili plant growth. The results showed that 7 isolates of actinomycetes were able to hydrolyze coffee pulp in vitro with a hydrolytic index of 1.7-3.81. The treatment of coffee pulp compost with the addition of a starter of cellulolytic actinomycetes (P2) at the end of the three-week incubation period showed the highest organic N (25 mg/kg), P (7.05 mg/kg), and K (33 mg/kg), t compared to other treatments. The effect of giving coffee pulp compost towards the growth of chili plants shows that  the coffee pulp composted with zeolite 5% (w/w) increased the height of the chili plants by 37.6%, while in coffee pulp composted by cellulolytic actinomycetes 5% (v/w) increased the number of leaves by 96% and plant biomass by 25%.  Based on the results of this research, coffee pulp compost has the potential to be used as biological fertilizer to increase plant growth, both composted by zeolite and cellulolytic actinomycetes

Wiraswati SM, Wahyudi AT, Rusmana I, Nawangsih AA. 2018. TRFLP analysis for revealing the diversity of rice phyllospherebacteria. Biodiversitas 19: 1743-1749. Phyllosphere environment of rice plant is usually inhabited by diverse bacteria which mostlycontribute beneficial effects to the plant fitness. TRFLP method is a rapid and straightforward method to determine the bacterialdiversity of many environments, including rice phyllosphere environment. This study aimed to analyze rice phyllosphere bacterialdiversity of healthy rice plant cultivar Ciherang obtained from Sukabumi, Jasinga, and Situgede. The bacterial genomes were amplifiedand digested with two restriction enzymes, i.e., MspI and BstUI. The bacterial diversity (H’ index) and evenness (E index) werecalculated from the peak value. From TRFs analysis, Betaproteobacteria and Pseudomonadales were dominantly found in nearly allsamples with different relative abundance. In addition, Alphaproteobacteria and Gammaproteobacteria were also dominant in the severalsamples. The unique bacteria groups were inhabited in the sample from specific regions with certain growth phase. This finding informsus that the geographical factors might be more influent than the growth phase factor. Furthermore, the bacterial diversity and evennessof the metagenomic approach are higher than cultivation-dependent approach.

The application of compost bedding system on sheep farm is a technology to minimize the negative impact of sheep manure waste toward environment. The microorganisms which inhabit the compost bedding, especially nitrifying bacteria are expected to have significant role in odor emission reduction which become environmental problem around the sheep farm. This study aims to analyze the abundance and diversity of nitrifying bacteria of compost bedding obtained from sheep farm which have important role in reducing odor emission of ammonia. The 12 days, 1 and 1,5 months old of compost bedding samples were obtained from sheepfold, while 3 and 4 months old of compost samples were obtained from compost pile. Furthermore, nitrifying bacteria were isolated from compost samples by pour plate method using specific media for Nitrosomonas and Nitrobacter. The results indicated that compost bedding samples with different composting time duration displayed different abundance and diversity of nitrifying bacteria. The current study was successfully isolated 39 and 47 nitrifying bacterial isolates using specific media for Nitrobacter and Nitrosomonas, respectively. The highest diversity of nitrifying bacteria was gained from 12 days old compost bedding sample. Nitrifying bacterial isolates from compost bedding samples have significant role in odor emission declining as well as manure composting at sheep farm. The obtained bacterial isolates are also potentially to develop as bio-activator for compost bedding.