Characterization and application of nitrogen-fixing and indole-3-acetic acid producing bacteria A13 in Oil Palm (Elaeisguineensis Jacq.) seedling

Oil palm plantations have a good prospect in Indonesia. One of the efforts to improve the productivity of oil palm plantation is the application of bacteria as biological fertilizer. The research was conducted to characterize and apply the nitrogen-fixing and indole-3-acetic acid producing bacteria in oil palm seedlings. The bacteria was isolated from soil samples which taken from Taman Nasional Bukit Dua Belas (TNBD) Jambi. Nitrogen free bromthymol blue (NFB) is used as media for nitrogen-fixing bacterial isolation. Selected isolate named A13 had an ability to form white pellicle on the surface of the semisolid medium, increased the pH, and changed the color of medium from green to blue Isolate A13 was identified as Gram-negative bacteria and had a rods shape. Analysis of 16S rRNA gene sequence showed that isolate A13 had a similarity with Pseudochrobactrum assacharolyticum. Hypersensitivity assay on tobacco leaves showed that isolate A13 was not a pathogen. During 48 hours of incubation, isolate A13 produced a maximum of IAA at the 24th hour of incubation. Isolate A13 produced 0.675 ppm of ethylene/hour in Acetylene Reduction Assay and 69,839 ppm of IAA in HPLC methods. This was the first report on nitrogen fixation and IAA production by Pseudochrobactrum assacharolyticum and its application in the soil of oil palm seedlings. Application of isolate A13 in oil palm seedling increased significantly the number of lateral roots, stem diameter, and height of plants

Biosynthesis and profiling of single cell carotenoids of Phaf ia rhodozyma in waste-based cultivation media

In order to investigate the feasibility of low-cost media for producing well- characterized single-cell carotenoid, the study on biosynthesis and profiling carotenoid in the yeast of Phaf ia rhodozyma was carried out. We have successfully identified the profiles of single-cell carotenoids of P. rhodozyma, which was cultivated in glucose-based medium (MG), molasses-based medium (MM), and coconut water-based medium (MC). Cells were separately cultured in those media under aerobic batch culture system to obtain the carotenoid profiles based on high performance liquid chromatography (HPLC) analysis. The results showed that medium composition strongly affects the profiles of P. rhodozyma carotenoids represented by ratio of astaxanthin and beta-carotene (ratio A/B). Astaxanthin was highly synthesized in cells cultivated in MG with ratio A/B as much of 20:1. On the other hand, MM and MC produced a lower ratio A/B than MG as much of 0.4:1 and 0.2:1, respectively. In addition, carotenoids profiles were detected more diverse when this yeast species was cultivated in two waste-based media. This study provided a basic physiological knowledge of P. rhodozyma cells for carotenoid biosynthesis using potential low cost cultivation m

Analysis of the SARS-CoV-2 envelope (E), nucleocapsid (N), and non-structural protein12 (nsp12) genes from COVID-19 patients in West Java

According to World Health Organization, as of January 2021, Indonesia is the only Southeast Asian country in which COVID-19 is still occurring in community transmission. West Java is one of the provinces holding the highest positive cases number. With the envelope (E), nucleocapsid (N), and non-structural protein 12 (nsp12) being the target genes of SARS-CoV-2 diagnostic kits and several antiviral drugs, the study of genetic variations has become relevant and greatly important. Out of 267 oro-nasopharyngeal swab specimens that were previously confirmed positive for COVID-19 in qPCR diagnostic test in Laboratorium Kesehatan Provinsi Jawa Barat, ten samples with acceptable qualities were selected and three samples were sequenced using Sanger sequencing. Nonsynonymous mutations were observed in the envelope gene (L21F) and in the nucleocapsid genes (R203K, G204R, A211S, and S193I). Phylogenetic analysis showed that samples were clustered with other sequences carrying identical mutations, but clustered non-discriminatively with all sequences when carrying no mutation. No pattern in geographical areas and clades, except for R203K-G204R for being a marker for the GR clade. Protein structure analysis showed that mutations observed did not change the hydrophobicity and the secondary structure of the nucleocapsid, while stability change (ΔΔG) showed that all mutations, aside from the R203K-G204R, have neutral effect on the protein stability. Therefore, it can be concluded that mutations observed in this experiment did not impart preference to disperse in certain geographical areas or cause any significant structural change in the protein.

Effect of Clove essential oil (Syzygium aromaticum) against the growth of dandruff scalps-causing fungal pathogen using Kirby- Bauer method in vitro

One of the strongest contributing factors in dandruff scalps is the presence of fungal pathogen or called as Malassezia. Several studies have found a connection between Malassezia and scalp health, one of which is caused by pathogenic fungal infections including Pityrosporum ovale, Microsporum gypseum, and Candida albicans. Clove flowers are known to contain eugenol and its derivative compounds which have antimicrobial, antifungal, antiseptic, and local anesthetic activity. This research aims to determine the effect of clove flower essential oil (Syzygium aromaticum) against some dandruff-causing fungi. The research method was to test the inhibitory power of clove flower essential oil using the diffusion method (Kirby Bauer technique). Samples of pathogenic fungi were cultured on SDA media (Saboroud Dextrose Agar) and given discs that had been given several concentrations of clove flower essential oil. The concentrations used were 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, positive control using 2% ketoconazole and negative control using virgin coconut oil (VCO). The results showed a significant effect between the ability of essential oils to inhibit the growth of some fungi that cause dandruff. The treatment of clove flower essential oil against M. gypseum at the concentration of 10% has an inhibitory ability of 33,05 mm and at the concentration of 100% amounted to 63.95 mm. Meanwhile, the inhibition percentage in P. ovale with a concentration of 10% and 100% of extract were 14,75 mm and 46,15 mm, respectively. The inhibition rate in C. albicans with the concentration of 10% extract and 100% of extract was 13,5 mm and 39,35 mm. The research shows that clove flower essential oil inhibits the growth of several pathogenic fungal in vitro.

Mycorrhiza stimulates Rhizobium infection in Paraserianthes falcataria (L.) I.C. Nielson under Hg contamination

Symbiosis of and AMF increase soybean production, but the information on the association between these microbes in Paraserianthes falcataria (L.) I.C. Nielson or ‘sengon’ under Hg contamination is limited. We observed P. falcataria inoculated with arbuscular mycorrhiza fungi (Glomus sp.) stimulate nodule formation under Hg contamination. The study was set up in a pot experiment in the growth chamber a the Hg concentration was adjusted to 50 ppm in soil medium. Inoculation of AMF stimulates nodule formation and increases P. falcataria tolerance to Hg. We isolated several bacteria from the rhizosphere belonging to Rhizobium group and others. Understanding the ecology of soil bacteria is important for Hg bioremediation using P. falcataria.

Effect of ethanol extract from Karuk leaf (Piper sarmentosum Roxb.) on the growth of Malassezia furfur in vitro

In Indonesia, there are numerous therapeutic plants found. Some of the plants used in herbal medicine are Karuk leaf (Piper sarmentosum Roxb.) belong to the Piperaceae family. Karuk leaf has chemical contents such as saponins, polyphenols, flavonoids, and essential oils and many tests are carried out on several bacteria, but testing of fungi is rarely studied. This study aims to determine the ethanol extract activities from karuk leaf in inhibiting the growth of the Malassezia furfur fungus and to determine its minimum inhibition by using the Kirby-Bauer method. The study was conducted by an experimental method of the M. furfur fungus using the Kirby-Bauer method. The ethanol extract from karuk leaf was made in various concentrations and tested on 0.5 McFarland fungus by diffusion on Sabouraud Dextrose Agar (SDA). The results of this analysis showed that the ethanol extract of Karuk leaf could inhibit the M. furfur fungus at a concentration of 30% by 5.3 mm, 40% by 6.6 mm, 50% by 7.6 mm, 60% by 11.3 mm, 70% by 12.5 mm, 80% by 15.6 mm, 90% by 17.4 mm, and 100% by 19.5 mm. Based on the results of the study and the data analysis, it can be concluded that several concentrations of ethanol extract of Karuk leaf affect the growth of M. furfur in vitro.

The influence of biocarrier of Aspergillus niger and Trichoderma harzianum toward vegetative growth of sorghum in the field experiment

Compared to other cereal crops, sorghum has a higher drought tolerance trait. However, efforts are needed to increase the productivity of sorghum, particularly in drought marginal land. One strategy to be implemented is the utilization of soil microorganisms formulated with biocarrier. Therefore, the aim of this study was to evaluate the influence of the fungal strain Aspergillus niger and Trichoderma harzianum formulated with compost and zeolite as biocarrier towards vegetative growth of sorghum. The field experiment was designed as a randomized block designed, factorial pattern with 4 replications. The first factor was selecting biocarrier, namely zeolite, compost, and a mixture of zeolite: compost (1:1). The second factor was the fungal inoculants, A. niger, and T. harzianum. The observed parameter was the growth profile of sorghum during vegetative growth, including stalk diameter and height. The results showed that the type of biocarrier, as well as the fungal strains did influence the growth of sorghum. The highest stalk diameter and height of sorghum were obtained after application of A. niger formulated with a mixture of zeolite: compost (1:1), with 17% and 41.2% higher than control, respectively. This condition shows that a mixture of zeolite and compost is seemingly able to create better micro-ecological conditions for fungal microbes to function effectively. Therefore, our findings suggested the addition of zeolite to compost for the application of biocarrier in the field experiment.

Culturable bacterial abundance in Volvariella volvacea cultivation medium and characterization of its bacteria

Straw mushroom (Volvariella volvacea) is one of the popular edible fungi in Indonesia. Previous researches showed the correlation among the type of substrate, substrate quality, and its composting process to the microbial community, yield, and biological efficiency. The aim of the research is to analyze the culturable bacteria abundance in straw mushroom cultivation medium, characterize the bacteria in several stages of mushroom cultivation and investigate the interaction between V. volvacea with its resident bacteria. Samples were taken from mushroom farmers in Subang and Karawang regencies, Indonesia. The materials for cultivation medium are the mixture of cotton and paddy straw and the pasteurization was performed at 65-70°C for 7 hours. The result shows the abundance of the bacteria in most of the cultivation stages is relatively similar i.e. 108 CFU/g, except in 15 days after inoculation (DAI), the bacterial abundance is lower i.e.6.24 x 107 CFU/g. Twenty-five isolates were obtained and Gram-positive bacteria is the dominant bacteria found in the cultivation medium, especially rod-shaped Gram-positive bacteria. According to co-culture assay there are nine isolates that decrease the growth rate and clearly inhibit mycelial growth. The other 10 isolates have lower inhibitory activity, and 6 isolates have no inhibitory activity to the mycelial growth. C38 isolates have the highest mycelial growth inhibition. It belongs to rod-shaped Gram positive group of bacteria which isolated from the early stage of V. volvacea cultivation medium (5 DAI).

Extraction, characterization, and biological toxicity of β-glucans from Saccharomyces cerevisiae isolated from ragi

β-glucan is a homopolysaccharide with biological activities that are beneficial to health as an immunostimulant, anti-inflammatory, anti-diabetic, anti-cholesterol, and many more. β-glucan extraction results from yeast require characterization related to this bioactive quality, such as β-glucan weight, monomer analysis, functional groups, and cytotoxicity assay. Four Saccharomyces cerevisiae isolates were isolated from three local ragi samples, namely the SC-1, SC-2, SC-3, and SAF from instant ragi. This study aimed to obtain the best candidate of S. cerevisiae isolates to produce high β-glucan levels and low protein levels and to test the potential for cytotoxicity. The four isolates were rejuvenated on potato dextrose agar (PDA), then inoculated into the liquid glucose yeast peptone (GYP) fermentation medium for six days. Saccharomyces cerevisiae cells were extracted by neutralizing acid-base, dried and weighed as a crude β-glucan (mg per 300 mL). The highest yield was SC-2 (818 mg), followed by SC-3 (726 mg), SAF (597 mg), and SC-1 (433 mg). The presence of –OH (alcohol), -C-C-C- (alkane), and –R-O-R- (ether) groups were showed using FTIR characterization. Glucose equivalent β-glucan levels and protein levels were determined using a UV-Vis spectrophotometer. The results showed that β-glucan SC-1 gave the best results with glucose equivalent β-glucan levels of 4,865% and protein levels of 3,804%. The crude β-glucan toxicity test using the brine shrimp lethality test (BSLT) method shows that the β-glucan of the SAF strain has LC50 cytotoxicity of 114.8 ppm followed by β-glucan cytotoxicity from local ragi LC50 was SC-2 (323.5 ppm), SC-1 (331.1 ppm), and SC-3 (354.8 ppm). Therefore, based on the results, SC-1 isolate obtained the highest β-glucan crude and the lowest protein content was SC-2. The β-glucan of SAF extract had the highest toxicity properties based on the IC50 value.