Pemanfaatan Biochar sebagai Pembawa Rhizobium terhadap Pembentukan Bintil Akar dan Hasil Tanaman Kedelai (Glycine max L. Merril)

The Utilization of Biochar as a Carrier of Rhizobium for the formation of root nodules and Yield of Soybean (Glycine max L. Merril). This study aims to determine the effect of the type of raw materials and particle size of biochar as a Rhizobium carrier on the formation of nodules in soybean plants. This research was conducted from September to November 2020 at the Experimental Station and Laboratory of Soil and Environmental Sciences, Faculty of Agriculture, Udayana University. The research design used was a randomized block design with nested patterns with 2 factorials and 3 replications. The treatment factors consisted of B1 = bamboo biochar, B2 = albasia wood biochar, B3 = corncob biochar, B4 = young coconut skin biochar, P1 = (0,15-0,50 mm), P2 = (>0,50-1,68 mm), P3 = (>1,68-3,36 mm). The parameters observed included effective nodule, nodule size, total bacterial population, ammonium, nitrate, and plant yield. The result of the analysis showed that the type of biochar raw materials had a very significant effect on the parameters of effective nodules, nodules size, total bacterial population and plant yield, but had no significant effect on soil chemical parameters. The treatment of biochar particle size had a very significant effect on the parameters of effective nodules, total bacterial population, and plant yield, and had a significant effect on the size of nodules, but had no significant effect on soil chemical parameters. The conclusion of this study is that the type of raw material for albasia wood biochar is effective as a Rhizobium carrier, which is indicated by the high number of effective nodules, nodules size and total bacterial population of 0,15-1,68 mm particles.

Lipolytic bacteria and the dynamics of flavor production in Indonesian tempeh

Nur N, Meryandini A, Suhartono MT, Suwanto A. 2020 Lipolytic bacteria and the dynamics of flavor production in Indonesian Tempeh. Biodiversitas 21: 3818-3825. During the process of tempeh maturation, lipolytic bacteria become an integral part of tempeh and even have important roles in determining the quality of resulting tempeh. This study was conducted to examine correlation between lipolytic bacteria which were present in three tempeh samples i.e. CMG, EMP, RTI, and their roles in liberation of free fatty acid. Lipolytic bacteria were found in each tempeh sample which were approximately 0.1 % of total bacterial population. CMG harbored the highest lipolytic bacterial population at 1.04 × 106 cfu g-1 followed by EMP at 2.88 × 105 cfu g-1, and RTI at 1.72 × 104 cfu g-1. Tempeh aroma and texture showed strong correlation between the numbers of bacterial population during the period or stages of tempeh maturation. Moreover, we also found a unique correlation between dynamic of lipolytic population and aroma changes. Free fatty acid profiling indicates that lipolysis activity was presence during fermentation of tempe where each tempeh samples showed some differences in liberation of dominant free fatty acid. 16S rRNA sequencing from a hundred of lipolytic isolates was identified and classified as member of the phylum Proteobacteria, Firmicutes, and Actinobacteria, other isolates were classified as uncultured clone.

Lactic-acid bacteria increase the survival of marine shrimp, Litopenaeus vannamei, after infection with Vibrio harveyi

This study evaluated the survival, post-larvae quality, and the population of bacteria in Litopenaeus vannamei after the addition of two strains of lactic-acid bacteria (2 and B6) experimentally infected by Vibrio harveyi. Fifteen hundred nauplii were distributed in 20 L capacity tanks with four replicates. The survival of control animals was lower (21%) than that of animals fed with the strains B6 (50%) and 2 (44%). Total bacterial population in the water and larvae, as well as of the Vibrio ssp. in water was not different among the treatments. No difference was observed in the population of Vibrio ssp. between the control larvae (5.5±0.5 log UFC/mL) and that fed with strain 2 (5.4±0.1 log UFC/mL). Shrimp from control and fed with strain 2 showed significantly higher bacterial population than those fed with strain B6 (1.2±0.2 log UFC/mL). It was detected the lower load of Vibrio ssp. bacteria with potential of pathogenicity after feeding with strain B6.Moreover, these larvae showed more active behavior and low number of necrosis in relation to the control group and to that fed with strain 2.

Involvement of Rhodocyclus-Related Organisms in Phosphorus Removal in Full-Scale Wastewater Treatment Plants

ABSTRACT The participation of organisms related to Rhodocyclus in full-scale enhanced biological phosphorus removal (EBPR) was investigated. By using fluorescent in situ hybridization techniques, the communities of Rhodocyclus-related organisms in two full-scale wastewater treatment plants were estimated to represent between 13 and 18% of the total bacterial population. However, the fractions of these communities that participated in polyphosphate accumulation depended on the type of treatment process evaluated. In a University of Cape Town EBPR process, the percentage of Rhodocyclus-related cells that contained polyphosphate was about 20% of the total bacterial population, but these cells represented as much as 73% of the polyphosphate-accumulating organisms (PAOs). In an aerated-anoxic EBPR process, Rhodocyclus-related PAOs were less numerous, accounting for 6% of the total bacterial population and 26% of the total PAO population. In addition, 16S ribosomal DNA sequences 99.9% similar to the sequences of Rhodocyclus-related organisms enriched in acetate-fed bench-scale EBPR reactors were recovered from both full-scale plants. These results confirmed the involvement of Rhodocyclus-related organisms in EBPR and demonstrated their importance in full-scale processes. In addition, the results revealed a significant correlation between the type of EBPR process and the PAO community.

Evidence for muramic acid in soil

Evidence indicative of the presence of muramic acid in soil was demonstrated. Muramic acid values ranging from 0 to 150 μg/g dry weight of soil were obtained for 33 different soil samples. Comparisons of these values with the muramic acid contents of laboratory-grown microbial cultures revealed that the soil muramic acid levels are about 100- to 1000-fold greater than can be accounted for by a platable bacterial population in soil, but are compatible with other estimates of total bacterial soil numbers. It was suggested that a muramic acid analysis of soil might provide an estimate of its total bacterial population.

SANITARY STATUS OF SOME PRECOOKED, FROZEN, DESSERT-TYPE FOODS1

Summary Sanitary status of 102 samples of precooked, frozen, dessert-type foods available in the local market (Manhattan, Kansas) was determined. Foods were studied for total bacterial population, densities of coliform bacilli, Escherichia coli and staphylococci. All samples except two showed standard plate counts fewer than 100,000 per g, and the majority (90%) had counts below, 41,000 per g. Thirty-nine (38.2%) of the specimens showed evidences of coliform contamination and 8 (7.8%) were contaminated with E. coli of probable fecal origin. Coliform counts in 24 (23.32%) samples varied from 10 to 275 per g. Twenty-eight (27.45%) of the specimens showed contamination by staphylococci though no isolate proved to be coagulase-positive. Some problems of analysis and interpretation that arose are discussed.

Studies of Fish Spoilage: IV. The Bacterial Reduction of Trimethylamine Oxide

In fish muscle press juice simulating the surface and the interior of muscle, there is an aerobic environment in the surface layer and an anaerobic environment in the body of the liquid. The Eh potential of the former is about 0.3 volts and of the latter from −0.5 to −0.10 volt.It is found that the bacterial population proliferating at 2 °C. is chiefly Achromobacter, which can be divided into two groups, obligate aerobes and facultative anaerobes. Only the latter group, which is capable of growth in the interior or surface, is responsible for the reduction of trimethylamine oxide with the evolution of trimethylamine. Since the initial total count is made up of a large number of obligate aerobes or non-oxide reducers it is obvious that the total bacterial population cannot be related to trimethylamine production. The appearance of this base therefore may be taken to indicate a bacterial population which is in excess of that responsible for its production.Molecular oxygen at surface exercises a trimethylamine oxide sparing effect. In practice, however, this effect is not significant from the point of view of the freshness test in the sense of Beatty and Gibbons.