Dea Indriani Astuti

Laboratory simulation of microbial enhanced oil recovery using Geobacillus toebii R-32639 isolated from the Handil reservoir

Microbial enhanced oil recovery (MEOR) is a biological based technology to enhance crude oil (CO) recovery at old oil wells by manipulating function or structure or both of the microbial environments existing in oil reservoirs. Even if many biosurfactant-producing microbes can be found in different environments, the ability of Geobacillus toebii R-32639 to enhance CO recovery needs to be verified. In this study, artificial cores (ACs) are used to simulate the application of MEOR by three scenarios of injecting nutrients, microbial culture and bioproducts. The use of Geobacillus toebii R-32639 as biosurfactant producer enables a lowering by 25.3% of interfacial tension and by 14.1% of CO viscosity and also enables the degrading of a 7.4–28.8% fraction of (C12–C34) hydrocarbons after 7 days of incubation. The injection of microbial culture into a laboratory-scale CO reservoir of the AC for the desirable purpose of enhanced oil recovery could feasibly achieve an average recovery factor of 14.27% but lower by 5.50% the AC porosity and by 91.0% the AC permeability; this is the best-case scenario of the microbial core flooding (MCF) experiments. The simulation of MEOR by using bacterial strains of Geobacillus toebii R-32639 provides valuable insight into the use of MCF experiments to obtain greater oil production from existing reservoirs.

The Use of Indigenous Probiotic Halomonas aquamarina and Shewanella algae for White Shrimp (Litopenaeus vannamei Boone) Hatchery Productivity in Zero Water Discharge System

This research was aimed to improve the performance of white shrimp postlarvae culture through the application of indigeneous probiotic bacteria, Halomonas aquamarina and Shewanella algae in zero water discharge system. The research was conducted by following two consecutive steps: (1) pathogenicity test of both probiotic in white shrimp culture, and (2) probiotic effect test to water quality and vibriosis syndrome control. From the first step, the use of probiotics had no pathogenocity effect to shrimp PL since survival rate of 84-98% was documented. From step two, the application of both probiotic bacteria was able to inhibit the population growth of V. harveyi in which the highest survival rate of 93.94% obtained from H. aquamarina addition, followed by S. algae addition (92.12%), H. aquamarina: S. algae addition (90.60%), S. algae: V. harveyi addition (89.39%), H. aquamarina: S. algae: V. harveyi addition (87.87%), H. aquamarina: V. harveyi addition (87.57%), no addition of bacteria (84.84%) and V. harveyi addition (82.42%). There was no significantly different (p>0.05) among the treatments on all water quality parameters which were still in tolerance range of white shrimp PL culture (salinity 26-30 ppt; temperature 26-28°C; pH 7.5-8.5; DO 5.7-6.4 mgL-1; ammonia 0.1-0.5 mgL-1; nitrite 0.02-0.25 mgL-1; nitrate 5-40 mgL-1). In term of other biological parameter, the use of these probiotics was significantly affecting the weight increase of shrimps. Bacterial identification showed that there was a major similarity of microbial diversity found both in water and L.vannamei intestine. It could be concluded that the use of H. aquamarina and S. algae as indigene probiotics contributed to the increase of shrimp survival rate. However this effect was not clearly described by the effect of water quality parameters improvement and it most probably due to the inhibition activity of these two probiotics on V. harveyi.

Use of Zero Water Discharge Technology through the Application of Nitrifying Bacteria and Textile Vertical Substrate in Grow-Out Phase of Macrobrachium rosenbergii De Man

This study was conducted to develop a zero water discharge technology for Macrobrachium rosenbergii growth in order to solve the unpredictability of prawn production during grow-out phase.The system consists of three major compartments: (1) Prawn culture tank, (2) Trickling biofilter for nitrification process, and (3) Textile vertical substrate for prawn territory expansion. The trial was conducted in three diferent stages: (1) nitrifying bacteria of 105 Colony Forming Units.mL-1(CFU.mL-1) was inoculated into the culture 24 hours prior to juvenile stocking and every 10 days during culture period, (2) the culture was grouped into five treatments: 30 individuals.m2 (control), 40 individuals.m2, 50 individuals.m2, 60 individuals.m2, and 70 individuals.m2, and (3) measurements of biological, physicochemical, and microbiological culture parameters. Optimum culture performance was obtained in the culture with initial stocking density of 30 individuals.m-2 (control) with final metabolic body weight, length, specific growth rate (SGR), survival rate (SR), feed conversion rate (FCR) of (11.37 ± 4.92) g, (10.69 ± 1.45) cm, 2.569%.day-1, 78.3%, and 0.99, respectively. However, from an economic perspective, stocking with 70 individuals.m-2 (treatment IV) produced the highest total final biomass (975 g) and highest profit (Rp. 19.285 per kg) compared to the other treatments. Results indicate that use of the developed zero-water discharge rearing system with the application of nitrifying bacteria and textile vertical substrate can maintain good water quality to support a higher stocking density, better growth and larval survival rate and profit of prawn M. rosenbergii de Man grow-out culture.

Potential Degradation of SARA (Saturated, Aromatics, Resinics, Asphaltenes) Fractions of Crude Oil by Reservoir Indigenous Bacteria from South Sumatera

The research aimed to isolate and characterize indigenous yeast strain from Tacca leontopetaloides with respect to the ethanol and glucose tolerance ability. Research done experimentally and the data analyzed descriptively. Yeasts isolated from 1g Tacca leontopetaloides grown at modified Potato Dextrose Agar/PDA (Oxoid Ltd.) with 3% Yeasts Extract/YE (Kraft Foods) and 10 ppm amoxicillin addition. Yeasts-like colony was tested in the ability to tolerate ethanol and glucose contents by grown on modified Nutrient Broth/NB (Oxoid Ltd.) with 3% Yeasts Extract/YE (Kraft Foods) and 10 ppm amoxicillin then added with glucose monohydrate (10%, 20%, 30%) or ethanol (10%, 20%, 30%) and incubated for 72h at ambient (23-28°C). Optical density (OD) was read for UV absorbance at 600 nm using UV-Vis spectrophotometer every 24h until 72h. The strain of best isolate with the ability to tolerate high ethanol and glucose contents were identified by the sequence analysis of ITS (Internal Transcribed Spacer) region using primers ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′). The sequencing was performed at Macrogen Inc. (Seoul, South Korea), and the sequences was compared with the GenBank database using BLAST (Basic Local Alignment Search Tools) algorithm (http//:www.ncbi.nlm.nih.gov/BLAST/). Results shown there are four yeasts-like isolate and the TK1 isolate showed the best ethanol tolerance ability with highest OD at 30% ethanol concentration (0.486) and the highest OD at 30% glucose concentration (1.732). The species identification identified the TK1 isolate as 99% identical with Candida natalensis (ITS1) and 100% identical with Candida quercitrusa (ITS4).Among Plant Growh Promoting Rhizobacteria (PGPR) groups, endophytic bacteria considered as one of the options to control vascular wilt disease because of its ability to live and colonized internal roots of plants without causing any damages. Our previous research had screened 9 isolates which had best ability to promote growth rate and increase yields of tomato and biocontrol agents of R. solanacearum and Fusarium oxysporum f.sp solani in planta condition. In order to know its abilities, those isolates need to be characterized. This research purposed to characterize those isolates abilities to produce IAA, phosphate solubilizing, siderophore production, cyanide production, NH3 production, and ability to colonize endophytically and identified the isolates using 16S rRNA. Result shown that all isolates can produce IAA, where TLE1.1 produce highest IAA concentration (42.5 ppm). Isolates E1AB1.3, TLE 1.1 and TLE2.2 can dissolved phosphate. None of the isolates produced HCN and NH3. Only TLE 2.3 isolate can produce siderophore. All of 9 isolates were identified using 16S rRNA gene using 27F and 1492R primers. All isolates were identified as different species, i.e. Bacillus toyonensis strain BCT-7112 (EPL1.1.3), Serratia nematodiphila strain DZ0503SBS1 (TLE2.3), Bacillus anthracis strain ATCC 14578 (EPL1.1.4), Bacillus cereus ATCC 14579 (TLE1.1), Bacillus cereus strain JCM 2152 (SNE2.2), Enterobacter cloacae subsp. dissolvens strain ATCC 23373 (E1.AB1.2), Serratia marcescens strain NBRC 102204 (E1AB2.1), Klebsiella michiganensis strain W14 (TLE2.2), and Chryseobacterium rhizoplanae strain JM-534 (KLE3.3).

Preliminary Study on Climate Change Biomitigation by Improving CO2 Removal and CO2 Utilization Efficiency Using Microalgae Culture in Photobioreactor

Culture conditions are very important to CO2 bio-fixation related with the CO2 removal efficiency through biological process by microalgae photosynthesis activities. The aim of the research was to study how high CO2 utilization efficiency could reach in mix culture that supplied high CO2 concentration (2%, 5%, and 7%) continuously from the bottom of photobioreactor. The mix microalgae culture containing of Chlorella sp, Scenedesmusobliquus and Ankistrodemus sp. were cultivated in photobioreactor with various environmental treatments i.e light intensities, light periodism and temperatures whereas the fixed CO2 gas flow rate of 8 L.min-1. The results showed that microalgae growth was best at light intensity of 4000 lux for 16/8 hours light/darkness cycling, 30°C and 5% CO2 supplied, indicated by the highest dried biomass (g.L-1), the highest Carbon content was g.d-1 and highest CO2 removal efficiency (%) that were 2.7, 11.9, 49, respectively. However the highest CO2 utilization efficiency for bio-fixation phenomenon was obtained from culture that supplied by 2% CO2 concentration, the value was almost 2 fold than 5% CO2 supplied and 4 fold than 7% CO2 concentration supplied, respectively. Biological fixation of CO2 are greatly affected by the characteristics of the microalgae strains and their tolerance to environmental conditions.