Continuous, dark fermentative hydrogen production technology using mixed microflora at mesophilic temperatures may be suitable for commercial development. Clostridial-based cultures from natural ...sources have been widely used, but more information on the need for heat treatment of inocula and conditions leading to germination and sporulation are required. The amount of nutrients given in the literature vary widely. Hydrogen production is reported to proceed without methane production in the reactor in the pH range 4.5–6.7, with hydraulic retention times optimally between a few hours and 3 days depending on substrate. Higher substrate concentrations should be more energy-efficient but there are product inhibition limitations, for example from unionised butyric acid. Inhibition by H
2 can be reduced by stirring, sparging or extraction through membranes. Of the reactor types investigated, while granules have the best performance with soluble substrate, for particulate feedstock biofilm reactors or continuous stirred tank reactors may be most successful. A second stage is required to utilise the fermentation end products which, when cost-effective reactors are developed, may be photofermentation or microbial fuel cell technologies. Anaerobic digestion is a currently-available technology and the two-stage process is reported to give greater conversion efficiency than anaerobic digestion alone.
Biotic nitrogen fi is a phenomenon mainly depended on mutualistic interrelation between host plant and root nodule bacteria. This interrelation affects photosynthesis and productivity of biological ...N-fixation and requires studies of biological particularities of grown legume cultivars and effectiveness of Bradyrhizobium strains used for seed inoculation. A field experiment was conducted on the territory of Nesvizhskaya Crop Testing Station (Minsk region, Republic of Belarus). Based on chlorophyll and nitrogen content in soybean leaves, number of nodules on roots of cultivars grown, and on quantity of nitrogen accumulated in plants, four soybean cultivars were assessed. The cultivar Pripyat (control) has poorly responded on inoculation, whereas cultivars Slavyankа an Sobrini responded well by increase of chlorophyll and nitrogen content in leaves and by larger number of root nodules. As a result, they produced unusually high seed yields. Therefore, these soybean cultivars may be recommended for wide use in regions of Belarus.
Chlorella vulgaris is one type of unicellular green microalgae with a cell diameter ranging from 2-8 microns. Pigments in Chlorella vulgaris besides functioning as antioxidant activity but also have ...a protective effect on retinal degeneration and strengthen the immune system. The purpose of this study was to determine the beta-carotene content of Microalgae Chlorella vulgaris cultured by treatment of light sources and different initial densities of inoculum. The method used was an experimental method, while the design of the study was a complete randomized factorial design consisted of 6 treatments and 3 repetitions. The treatments were light sources neon (32 watt) with an additional red LED, green LED and blue LED each for 16 watt with the Chlorella vulgaris inoculum initial density that was cultivated were 10x104 and 100x104 cells/ml. The result showed that the highest β-carotene content was 721,572 mg/l in the blue LED with inoculum initial density of 100x104 cells/ml.
Telah dilakukan penelitian tentang prediksi konsentrasi inokulum dan umur fermentasi pada tempe menggunakan sistem larik sensor gas. Sistem larik sensor gas terdiri dari 3 subsistem yaitu pengindera, ...elektronik, dan pengolahan data. Subsistem pengindera dirancang menggunakan sensor MQ-3, MQ-4, dan MG-811 yang masing-masing peka terhadap perubahan kadar gas alkohol, metana, dan karbondioksida. Sebagai subsistem elektronik digunakan mikrokontroler ATMega328P yang berfungsi sebagai elemen pemroses data keluaran dari sensor gas. Sedangkan sebagai subsistem pengolahan data digunakan Jaringan Syaraf Tiruan (JST) propagasi balik sebagai salah satu metode prediksi yang akurat. Hasil simulasi menunjukkan bahwa model mampu mengikuti pola keluaran konsentrasi inokulum dan umur fermentasi tempe dengan korelasi yang sama yaitu 0,99, dengan MSE (Mean Squared Error) sebesar 1,78.10-4 dan 8,83.10-4. Nilai korelasi konsentrasi inokulum dan umur fermentasi menggunakan data pengujian masing-masing sebesar 0,98 dan 0,99 dengan MSE 8,92.10-5 dan 2,31. 10-3 .
The development of seeds at various positions in the pod is asynchronous. Thus, the differences of seed dry mass production because of environmental conditions may depend on the cultivar type, type ...of inoculants and interrelations between seeds per pod, pods per plant or seeds per plant. Presently, a mathematical description of pea seed categorisation is missing. The aim of the study was the assessment of two groups of variables (quantitative and qualitative) for pea seed weight categorisation by ordinal regression model. Year, cultivar and inoculant constituted the first group (qualitative variables), whilst seeds per pod, the pods per plant and seeds per plant (quantitative variables) were entered as covariates in the ordinal regression model. According to the ordinal regression model variables, seeds per pod, pods per plant, seeds per plant, year and cultivar are meaningful predictors of the seed mass categories. However, the variable inoculant is marginally significant.
Abstrak Tujuan penelitian ini adalah mengetahui pengaruh dari persentase inokulum dan waktu inkubasi terhadap kemampuan isolat bakteri asetogenik untuk memproduksi total asam tertinggi serta ...mengetahui karakteristik dari isolat bakteri tersebut. Rancangan Acak Kelompok (RAK) disusun secara faktorial dengan dua faktor yaitu persentase inokulum (I) (10%, 15%, 20%) serta faktor waktu inkubasi (W) (24 jam, 48 jam, 72 jam). Kombinasi perlakuan terbaik pada isolat bakteri asetogenik dalam menghasilkan asam adalah I1W1, yakni persentase inokulum 10% dan waktu inkubasi 24 jam. Pada perlakuan ini kadar asam asetat yang dihasilkan adalah 3,853%, pH 5,544, total bakteri 7,7 x 107 CFU/ml, dengan kadar glukosa 2,5237%. Karakteristik dari isolat bakteri asetogenik terpilih secara morfologi koloni yaitu memiliki kenampakan warna putih, bentuk tidak beraturan, permukaan (elevasi) datar, dan tepi yang bergelombang. Berdasarkan morfologi sel, isolat bakteri merupakan bakteri Gram negatif bentuk batang. Berdasarkan identifikasi secara biokimia, isolat bakteri ini adalah Acinetobacter sp dengan probabilitas 51,25%. Kata kunci: asam asetat, bakteri asetogenik, isolasi, persentase inokulum, waktu inkubasi Abstract The purpose of this research was to understand the effect of inoculum percentage and incubation time of acetogenic bacteria to produce total acid and to understand the characteristics of acetogenic bacteria that could produce the highest total acid. The experimental design used was Randomized Block Design that arranged in factorial with two factors: percentage of inoculum (I) (10%, 15%, 20%) and the factor Incubation time (W) (24 hours, 48 hours, 72 hours). The best treatment combination on isolated acetogenic bacteria to produce total acid was I1W1 (10% inoculum percentage and 24 hours incubation time ). This treatment produced 3.853% acetic acid levels, 5.544 pH, 7.7 x 107 CFU / ml total bacteria and 2.5237% glucose levels. The characteristics of isolated acetogenic bacteria based on colony morphology was white, irregular shape, surface (elevation) flat, and wavy edges. Based on cell morphology, the isolated bacteria were Gram-negative rod shape. Based on the biochemical identification, the isolated bacteria is an Acinetobacter sp with 51.25% probability. Keywords: acetic acid, acetogenic bacteria, isolation, percentage of inoculum, incubation time
Biohydrogen could efficiently be produced in glucose-fed biofilm reactors filled with plastic carriers and operated at 70°C. Batch experiments were, in addition, conducted to enrich and cultivate ...glucose-fed extreme-thermophilic hydrogen producing microorganisms from a biohydrogen CSTR reactor fed with household solid waste. Kinetic analysis of the biohydrogen enrichment cultures show that substrate (glucose) likely inhibited hydrogen production when its concentration was higher than 1 g/L. Different start up strategies were applied for biohydrogen production in biofilm reactors operated at 70°C, and fed with synthetic medium with glucose as the only carbon and energy source. A biofilm reactor, started up with plastic carriers, that were previously inoculated with the enrichment cultures, resulted in higher hydrogen yield (2.21 mol H₂/mol glucose consumed) but required longer start up time (1 month), while a biofilm reactor directly inoculated with the enrichment cultures reached stable state much faster (8 days) but with very low hydrogen yield (0.69 mol H₂/mol glucose consumed). These results indicate that hydraulic pressure is necessary for successful immobilization of bacteria on carriers, while there is the risk of washing out specific high yielding bacteria. Biotechnol. Bioeng. 2008;100: 1034-1038.
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