The growth inhibition of Aspergillus flavus and Fusarium moniliforme by extract of seruni ( Wedelia biflora ) and Kembang bulan ( Tithonia diversifolia ) has studied. Kirby-Bauer disc diffusion were used in this experiment. The leaf methanolic extracts prepared were 0, 5, 10, 15, 30, 40, 50, 60 and 70% with d imethyl sulfoxide as the solvent. The results showed that extract of seruni and kembang bulan has a different activity in inhibiting the growth of both fungus. Seruni extract showed lower activity in inhibiting A. flavus and F. moniliforme than kembang bulan. In 40% seruni inhibits the growth both of the fungus. While kembang bulan showed activity in inhibiting A. flavus and F. moniliforme in 5%. Kata kunci: A . flavus , F. moniliforme, T. diversifolia and W. biflora exctract
Abstract. Bukhori A, Suryanto D, Nurtjahja K. 2022. Biosurfactant activity of phylloplane bacteria from an ornamental plant, Colocasia esculenta L. Biodiversitas 23: 3108-3114. Biosurfactants are surface-active molecules produced by living organisms predominantly by microorganisms with amphiphilic properties. Exploration of biosurfactant-producing bacteria has been promoted to find the suitable agent for mass production in the laboratory following its biochemical and genetic modification. Leaf-colonizing bacteria or phyllosphere bacteria are of great interest, including those colonizing the surface of ornamental plants which are still understudied. This study aimed to isolate the biosurfactant-producing bacteria from an ornamental plant, Colocasia esculenta L and to determine their physical characteristics. Four bacterial isolates coded as IC1, IC3, IC4 and IC5 were recovered from the surface of C. esculenta and were tested positive for their growth under Bushnell-Haas agar + 1% olive oil (v/v) as the sole carbon source. Two isolates, namely IC3 and IC5, later molecularly identified as Bacillus cereus and Alcaligenes faecalis produced the highest biosurfactant concentration (IC3 = 157 ppm, IC5 = 106 ppm) on 10th day incubation based on a colorimetric test using rhamnolipid as a standard solution. Crude biosurfactants produced by A. faecalis IC5 showed better physical attributes than B. cereus IC3 in terms of surface tension, emulsification index, and oil spreading capability on four different hydrophobic compounds i.e., kerosene, solar fuel, octane fuel (Pertalite, Pertamax). The results of this study confirmed the existence of biosurfactant-producing bacteria in C. esculenta and the possibility of developing prominent strains for the treatment of hydrocarbon pollution in the environment.
Abstract The rhizosphere has been known to contain rich microbial community which is directly influenced by secretions of roots. Rhizosphere microbes are known to have various benefits such as protection of plant from pathogens and toxic compounds, producing plant growth hormone, nitrogen fixation, and solubilizing phosphate. The objective of this study was to obtain rhizosphere bacteria capable of inhibiting the growth Fusarium oxysporum which is common pathogen attaching Capsicum annum. Bacteria were isolated from rhizosphere C. annum of local farm in Kabanjahe North Sumatra. Nine isolates based on morphological performance and biochemical analyses were obtained. Antagonistic test showed that two isolates BR6 and BR9 inhibited the growth of F. oxysporum with inhibition rate of 60% and 52%, respectively after 7 days incubation. These isolates also exhibited the activity to solubilize phosphate in Pikovskaya media with solubility index of 3.04 and 2.77, respectively. The other isolate BR5 even showed higher phosphate solubility index (3.42). These results suggest these isolates may have important role to support the growth of C. annum by providing protection from pathogens and phosphate ion. Then, study on the control of F. oxysporum attack on C. annum seedlings using these potential isolates is in process in our laboratory, as well as their molecular identification based on 16S rRNA.
The study was carried out to enumerate fungal contamination, and toxigenicity of Aspergillus flavus strains on cacao beans during drying and storage. As many as 3500 g cacao beans during drying and storage were purchased from smallholder farmers on the plantation areas at Karo Regency, Northern Sumatera. The percentage of the beans contaminated by fungi was conducted using direct plating. Fungal populations on soil and beans were determined using dilution followed by pour plated in dichloran 18% glycerol agar (DG18) and Aspergillus flavus and parasiticus agar (AFPA). The mycological evaluation was carried out based on morphological characteristics. Results showed eighteen genera of soil fungi were isolated at the cacao plantation; genera of Aspergillus sp., A. niger, A. flavus, and Penicillium citrinum were the most important contaminants. Six species of the fungi were associated with contamination on cocoa beans during drying i.e. Aspergillus sp., Candida tropicalis, Saccharomyces sp., A. niger, Penicillium spp., and Fusarium spp. Whereas three fungal species were associated during storage i.e. A. niger, A. flavus, and P. citrinum. The percentage of cacao contaminated during drying and storage was dominated (>40%) by Aspergillus sp. Fusarium sp. A. niger, A. flavus, and P. citrinum, respectively. Among 21 strains of A. flavus, 3 strains (15%) were isolated from soil, and 18 strains (85%) were isolated from beans during storage. Among toxigenic A. flavus, both strain scaf6 isolated from soil and strain cbaf5 isolated from beans during storage were the highest aflatoxin producers (30.0 ppb). Preventing soil contamination during harvesting, drying, and storage of cacao beans was a prerequisite to minimise fungal contamination.
Our knowledge of the distribution of macromycetes, both basidiomycetes and ascomy- cetes, in Indiana is wanting. A survey of the various herbaria within Indiana revealed only nine containing fungal specimens and most having fewer than 400 collections. Due to the immense importance of the newly-established Indiana Biological Survey to the future understanding of the biota of Indiana and due to the paucity of information pertaining to the fleshy mushroom flora and its distribution in Indiana, especially east-central Indiana, this study, to provide a brief description of lignicolous fungi occurring in Ginn Woods, Delaware County, was undertaken. The survey identified 60 species of lignicolous macro- mycetes, including 52 species of basidiomycetes and 8 species of ascomycetes. The 52 species of basid- iomycetes represented 38 genera from 23 families and 13 orders, and the 8 species of ascomycetes rep- resented 7 genera from 5 families and three orders. This is the first report, including voucher specimens, of these 60 fungi from Delaware County, Indiana.
Aspergillus flavus is one of the important fungus which can cause nutmeg deterioration during storage. The study aimed to investigate the effect of gamma irradiation 5 and 10 kGy on conidial germination and successive growth Aspergillus flavus strains isolated from nutmeg kernels up to 20 generations. Thirteen strains of the A. flavus were sub-cultured in potato dextrose agar (6 days, 28 °C). Conidia of each strain were harvested and one mL (107 conidia per mL) in 1.5 mL eppendorf tube were centrifuged 6000 ×g, air-dried (24 h, 28 °C) and irradiated at 5 and 10 kGy. Experiments were done in triplicate for each irradiation dose. Conidia with no irradiation used as control. After irradiation, conidia were re-suspended in 1 mL sterile distilled water. Serial dilutions were made and plated onto Aspergillus flavus and Parasiticus agar. Morphological characteristics such as colony diameter, mycelial branches, conidiophore and mycelial growth up to 20 generations were compared between irradiated and non-irradiated strains. Results showed that gamma irradiation up to 10 kGy inhibit conidial germination and mycelial growth of surviving strains. Successive growth of irradiated A. flavus up to 20 generations showed that their colony tend to grow and recover to their normal growth.
Abstract Isolation of soil fungi from landfill in Medan, North Sumatera, Indonesia was conducted. The aim was to investigate the fungal that potential to decolorize waste liquid batik home industry. Results showed that twenty-three species of filamentous fungi were successfuly isolated. All of the isolates were cultured in minimum salt medium containing waste liquid batik at concentration 25, 50, and 75%. At 75% waste, only 4 fungal isolates (Ys02, Ys13, Ys14, and Ys21) showed growth response. Cultured of the fungal isolates in minimum salt medium with 25% waste + 0.5% glucose were found three fungal isolates (Ys02, Ys14, and Ys21). Whereas, medium with 25% waste with no glucose were found only two fungal isolates (Ys14, and Ys21).
