Co-production of DHA and squalene by thraustochytrid from forest biomass.

Omega-3 fatty acids, and specifically docosahexaenoic acid (DHA), are important and essential nutrients for human health. Thraustochytrids are recognised as commercial strains for nutraceuticals production, they are group of marine oleaginous microorganisms capable of co-synthesis of DHA and other valuable carotenoids in their cellular compartment. The present study sought to optimize DHA and squalene production by the thraustochytrid Schizochytrium limacinum SR21. The highest biomass yield (0.46 g/gsubstrate) and lipid productivity (0.239 g/gsubstrate) were observed with 60 g/L of glucose, following cultivation in a bioreactor, with the DHA content to be 67.76% w/wtotal lipids. To reduce costs, cheaper feedstocks and simultaneous production of various value-added products for pharmaceutical or energy use should be attempted. To this end, we replaced pure glucose with organosolv-pretreated spruce hydrolysate and assessed the simultaneous production of DHA and squalene from S. limacinum SR21. After the 72 h of cultivation period in bioreactor, the maximum DHA content was observed to 66.72% w/wtotal lipids that was corresponded to 10.15 g/L of DHA concentration. While the highest DHA productivity was 3.38 ± 0.27 g/L/d and squalene reached a total of 933.72 ± 6.53 mg/L (16.34 ± 1.81 mg/gCDW). In summary, we show that the co-production of DHA and squalene makes S. limacinum SR21 appropriate strain for commercial-scale production of nutraceuticals.

Cost analysis of oil cake-to-biodiesel production in packed-bed micro-flow reactors with immobilized lipases.

Biodiesel production depends to a great extent on the use of cheap raw materials, since biodiesel itself is a mass product, not a high-value product. New processing methods, such as micro-flow continuous processing combined with enzymatic catalysis, open doors to the latter. As reported here, the window of opportunity in enzyme-catalyzed biodiesel production is the conversion of waste cooking oil. The main technological challenge for this is to obtain efficient immobilization of the lipase catalyst on beads. The beads can be filled into tubular reactors where designed packed-bed provide porous channels, forming micro-flow. It turns out, that in this way, the immobilization costs become the decisive economic factor. This paper reports a solution to that issue. The use of oil cake enables economic viability, which is not given by any of the commercial polymeric substrates used so far for enzyme immobilization. The costs of immobilization are mirrored in the earnings and cash flow of the new biotechnological process.

Enhancing Electricity Generation Using a Laccase-Based Microbial Fuel Cell with Yeast Galactomyces reessii on the Cathode.

The fungi associated with termites secrete enzymes such as laccase (multi-copper oxidase) that can degrade extracellular wood matrix. Laccase uses molecular oxygen as an electron acceptor to catalyze the degradation of organic compounds. Owing to its ability to transfer electrons from the cathodic electrode to molecular oxygen, laccase has the potential to be a biocatalyst on the surface of the cathodic electrode of a microbial fuel cell (MFC). In this study, a two-chamber MFC using the laccase-producing fungus Galactomyces reessii was investigated. The fungus cultured on coconut coir was placed in the cathode chamber, while an anaerobic microbial community was maintained in the anode chamber fed by industrial rubber wastewater and supplemented by sulfate and a pH buffer. The laccase-based biocathode MFC (lbMFC) produced the maximum open circuit voltage of 250 mV, output voltage of 145 mV (with a 1,000 Ω resistor), power density of 59 mW/m2, and current density of 278 mA/m2, and a 70% increase in half-cell potential. This study demonstrated the capability of laccase-producing yeast Galactomyces reessii as a biocatalyst on the cathode of the two-chamber lbMFC.

Cost effectiveness of phosphorus removal processes in municipal wastewater treatment.

Meeting stringent phosphorus (P) discharge standards remains one of the major challenges for wastewater utilities due to increased economic burdens associated with advanced (i.e., secondary, tertiary) treatment processes. In a trade-off between higher treatment cost and enhanced P removal, it is critical for the treatment plants to be able to select the most appropriate technology. To this end, established/emerging high performing P removal/recovery technologies (e.g., Modified University of Cape Towne process, Bardenpho process, membrane bioreactors, IFAS-EBPR, struvite recovery, tertiary reactive media filtration) were identified and full-scale treatment plant designs were developed. Using advanced mathematical modeling techniques, six different treatment configurations were evaluated in terms of performance and cost effectiveness ($/lb of P removed). Results show that the unit cost for P removal in different treatment alternatives range from $42.22 to $60.88 per lb of P removed. The MUCT BNR + tertiary reactive media filtration proved to be one of the most cost effective configurations ($44.04/lb P removed) delivering an effluent with total P (TP) concentration of only 0.05 mg/L. Although struvite recovery resulted in significant reduction in biosolids P, the decrease in effluent TP was not sufficient to meet very stringent discharge standards.

Comparison of batch cultivation strategies for cost-effective biomass production of Micractinium inermum NLP-F014 using a blended wastewater medium.

Two competitive strategies, fed-batch and sequencing-batch cultivation, were compared in cost-effective biomass production of a high lipid microalgae, Micractinium inermum NLP-F014 using a blended wastewater medium. For fed-batch cultivations, additional nutrient was supplemented at day 2 (FB1) or consecutively added at day 2 and 4 (FB2). Through inoculum size test, 1.0g-DCWL-1 was selected for the sequencing-batch cultivation (SB) where about 65% of culture was replaced with fresh medium every 2days. Both fed-batch cultivations showed the maximum biomass productivity of 0.95g-DCWL-1d-1, while average biomass productivity in SB was slightly higher as 0.96±0.08g-DCWL-1d-1. Furthermore, remained concentrations of organics (426mg-CODL-1), total nitrogen (15.4mg-NL-1) and phosphorus (0.6mg-PL-1) in SB were much lower than those of fed-batch conditions. The results suggested that SB could be a promising strategy to cultivate M. inermum NLP-F014 with the blended wastewater medium.

Forward osmosis membrane bioreactor for wastewater treatment with phosphorus recovery.

A forward osmosis membrane bioreactor (OMBR) with a thin film composite membrane was seeded with flocculated sludge and aerobic granules to treat a synthetic wastewater with 1M NaCl as draw solution. The tested OMBR showed 96%, 43% and 100% removal of PO4(3-)-P, NH4(+)-N, and total organic carbon. Salinity was accumulated in OMBR principally owing to membrane rejection and salt leakage from draw solution. At high salinity level membrane fouling could be induced. Intermittent withdrawal and replenishment of supernatant from OMBR maintained its operation stability, while phosphorus in withdrawn supernatant was recovered by pH adjustment. The OMBR enriched phosphorus concentration from 156 mg/L in feed solution to 890-990 mg/L. At pH 8.5 with 2.65-2.71 g 3 M NaOH/g-P, 814-817 mg-P/L was recovered in the form of sodium hydrogen phosphite hydrate. The OMBR is a volatile wastewater treatment unit with capability for enrichment and recovery of phosphorus at reduced chemical costs.

Optimization of cultural conditions for biosurfactant production by Pleurotus djamor in solid state fermentation.

Being eco-friendly, less toxic, more biodegradable and biocompatible, biological surfactants have higher activity and stability compared to synthetic ones. In spite of the fact that there are abundant benefits of biosurfactants over the synthetic congeners, the problem related with the economical and large scale production proceeds. The utilization of several industrial wastes in the production media as substrates reduces the production cost. This current study aims optimization of biosurfactant production conditions by Pleurotus djamor, grown on sunflower seed shell, grape wastes or potato peels as renewable cheap substrates in solid state fermentation. After determination of the best substrate for biosurfactant production, we indicate optimum size and amount of solid substrate, volume of medium, temperature, pH and Fe(2+) concentrations on biosurfactant production. In optimum conditions, by reducing water surface tension to 28.82 ± 0.3 mN/m and having oil displacement diameter of 3.9 ± 0.3 cm, 10.205 ± 0.5 g/l biosurfactant was produced. Moreover, chemical composition of biosurfactant produced in optimum condition was determined by FTIR. Lastly, laboratory's large-scale production was carried out in optimum conditions in a tray bioreactor designed by us and 8.9 ± 0.5 g/l biosurfactant was produced with a significant surface activity (37.74 ± 0.3 mN/m). With its economical suggestions and applicability of laboratory's large-scale production, this work indicates the possibility of using low cost agro-industrial wastes as renewable substrates for biosurfactant production. Therefore, using economically produced biosurfactant will reduce cost in several applications such as bioremediation, oil recovery and biodegradation of toxic chemicals.

Techno-economic evaluation of the application of ozone-oxidation in a full-scale aerobic digestion plant.

This paper deals with the application of the ozone-oxidation in a full scale aerobic sludge digester. Ozonation was applied continuously to a fraction of the biological sludge extracted from the digestion unit; the ozonated sludge was then recirculated to the same digester. Three different ozone flow rates were tested (60,500 and 670g O3 h(-1)) and their effects evaluated in terms of variation of the total and soluble fractions of COD, nitrogen and phosphorous, of total and volatile suspended solids concentrations and Sludge Volume Index in the aerobic digestion unit. During the 7-month operation of the ozonation process, it was observed an appreciable improvement of the aerobic digestion efficiency (up to about 20% under the optimal conditions) and of the sludge settleability properties. These results determined an average reduction of about 60% in the biological sludge extracted from the plant and delivered to final disposal. A thorough economic analysis showed that this reduction allowed to achieve a significant cost saving for the plant with respect to the previous years operated without ozonation. Furthermore, it was determined the threshold disposal cost above which implementation of the ozone oxidation in the aerobic digestion units of similar WWTPs becomes economically convenient (about 60€t(-1) of sludge).

Industrial waste utilization for low-cost production of raw material oil through microbial fermentation.

In view of ever-growing demand of biodiesel, there is an urgent need to look for inexpensive and promising renewable raw material oils for its production. In this context, the aim of this study was to evaluate the potential use of industrial wastes for low-cost production of oils through microbial fermentation. Among the strains tested, Yarrowia lipolytica grew best and produced highest lipid when grown on decanter effluent from palm oil mill. When crude glycerol by-product from a biodiesel plant was added into the effluent as a co-substrate, Y. lipolytica produced a higher biomass of 3.21 g/L and a higher amount of lipid of 2.21 g/L which was 68 % of the dry weight. The scale up and process improvement in a 5-L bioreactor increased the biomass and lipid up to 5.53 and 2.81 g/L, respectively. A semi-continuous mode of operation was an effective mode for biomass enhancement while a fed-batch mode was effective for lipid enhancement. These yeast lipids have potential to be used as biodiesel feedstocks because of their similar fatty acid composition to that of plant oil.

Influence of particles properties on biofilm structure and energy consumption in denitrifying fluidized bed bioreactors (DFBBRs).

The influence of particles properties on biofilm structure, reactor performance, and energy consumption for denitrifying fluidized bed bioreactors (DFBBRs) using maxi-blast plastic (MX), multi-blast plastic (MB), natural zeolite (NZ), and lava rock (LR) was investigated. The work showed that the particles with sphericity of 0.9 (MB and NZ) maintained a fluffy protruding biofilm and achieved slightly higher nutrient removal efficiencies as compared to the particles with sphericity of 0.5 (MX and LR) which exhibited a patchy biofilm at low C/N ratio. As a results, lower detachment rate and biomass yields were observed for MB and NZ of 0.12 g VSS/g COD, as compared to 0.19 g VSS/g COD for both the MX and LR. This study showed that increasing the biofilm thickness, though not significantly impacting nutrient removal efficiencies, would decrease the annualized energy costs and therefore reduce the long-term operational cost. Moreover, MB appears to be the superior media.

Process model and economic analysis of ethanol production from sugar beet raw juice as part of the cleaner production concept.

The batch fermentation process of sugar beet processing intermediates by free yeast cells is the most widely used method in the Autonomous Province of Vojvodina for producing ethanol as fuel. In this study a process and cost model was developed for producing ethanol from raw juice. The model can be used to calculate capital investment costs, unit production costs and operating costs for a plant producing 44 million l of 99.6% pure ethanol annually. In the sensitivity analysis the influence of sugar beet and yeast price, as well as the influence of recycled biomass on process economics, ethanol production costs and project feasibility was examined. The results of this study clearly demonstrate that the raw material costs have a significant influence on the expenses for producing ethanol. Also, the optimal percentage of recycled biomass turned out to be in the range from 50% to 70%.

Economic assessment of batch biodiesel production processes using homogeneous and heterogeneous alkali catalysts.

An economic feasibility study on four batch processes for the production of biodiesel ranging from 1452 tonnes/year (5000 l/day) to 14,520 tonnes/year (50,000 l/day) is conducted. The four processes assessed are the (1) KOH-W process, characterized by a homogeneous KOH catalyst and hot water purification process; (2) KOH-D process, characterized by a homogeneous KOH catalyst and vacuum FAME distillation process; (3) CaO-W process, characterized by a heterogeneous CaO catalyst and hot water purification process; and (4) CaO-D process, characterized by a heterogeneous CaO catalyst and vacuum FAME distillation process. The costs of the waste cooking oil, fixed costs, and manufacturing costs for producing 7260 tonnes/year (25,000 l/day) of biodiesel by means of the four processes are estimated to be $248-256, $194-232, and $584-641 per tonne of biodiesel, respectively. Among the four processes, the manufacturing costs involved in the CaO-W process are the lowest, in the range from 1452 tonnes/year to 14,520 tonnes/year.

[Lipid biofuel production with microalgae: potential and challenges]. / La production de biocarburant lipidique avec des microalgues : promesses et défis.

Microalgae can accumulate fatty acids up to 80% of their dry weight (Chisti 2007). As a consequence the yield per hectare could be higher by a factor of 30 compared to terrestrial oleaginous species. Biodiversity of microalgae is enormous. It is estimated that there are between 200 000 and several million species. Such diversity is an unexplored potential for research and industry. In comparison to terrestrial oleaginous species, microalgae have many characteristics addressing environmental problems with a drastically enhanced oil production. Microalgae are currently generating mediatic enthusiasm, and many start-ups are investing this niche. Nevertheless there are still locks to undo via upstream search, before the expected returns and costs are met and before these technologies can be developed at a large scale.

Scale-up of upstream and downstream operations for the production of glucosamine using microbial fermentation.

Glucosamine is used to treat osteoarthritis or as a nutritional supplement. The synthesis, isolation, and purification of glucosamine play a crucial role in its industrial application. This work presents the production of glucosamine from microbial fermentation, and discusses the production problems at both the upstream and downstream operations when the fermentation process is scaled up. The cost evaluation of process design was used to analyze the feasibility of using microbial fermentation for the production of glucosamine. The calculated result shows that the cost of the production of glucosamine should be designed to be approximately between US$200 and 300/kg for the project to be viable.

Production of medium-chain-length polyhydroxyalkanoates by Pseudomonas aeruginosa with fatty acids and alternative carbon sources.

In this study, medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were produced by Pseudomonas aeruginosa using different carbon sources. Decanoic acid induced the highest (9.71% [+/- 0.7]) mcl-PHAs accumulation in bacterial cells at 47 h. The cells preferred to accumulate and degrade the polyhydroxyoctanoate than polyhydroxydecanoate (PHD) during early stage and final stage of the growth, respectively. The production cost of mcl-PHAs can be reduced by using edible oils as the carbon source. The bacteria accumulated 6% (+/- 0.7) of mcl-PHAs in the presence of olive oil. Besides, reused oil was another potential carbon source for the reduction of the production cost of mcl-PHAs. Overall, PHD was the major constituent in the accumulated mcl-PHAs.

Development of MBR with reduced operational and maintenance costs.

To reduce MBR O&M costs, a new MBR process that conducts efficient simultaneous biological nitrogen and phosphorus removal (BNR) was developed. In the development of this process, various approaches were taken, including reduction of power demand, chemical consumption and sludge disposal costs. To address power demand reductions, air supply requirements for membrane cleaning were reduced. The process adopted an improved membrane that requires less air for cleaning than conventional membranes. It also introduced cyclic aeration, which alternately supplies washing air to the two series of membrane units. Adoption of biological phosphorus removal eliminated chemical costs for phosphorus removal and contributed to the reduction of sludge disposal costs. By combining these technologies, compared to conventional MBR processes, an approximately 27% reduction in O&M costs was achieved.

A process model to estimate biodiesel production costs.

'Biodiesel' is the name given to a renewable diesel fuel that is produced from fats and oils. It consists of the simple alkyl esters of fatty acids, most typically the methyl esters. We have developed a computer model to estimate the capital and operating costs of a moderately-sized industrial biodiesel production facility. The major process operations in the plant were continuous-process vegetable oil transesterification, and ester and glycerol recovery. The model was designed using contemporary process simulation software, and current reagent, equipment and supply costs, following current production practices. Crude, degummed soybean oil was specified as the feedstock. Annual production capacity of the plant was set at 37,854,118 l (10 x 10(6)gal). Facility construction costs were calculated to be US dollar 11.3 million. The largest contributors to the equipment cost, accounting for nearly one third of expenditures, were storage tanks to contain a 25 day capacity of feedstock and product. At a value of US dollar 0.52/kg (dollar 0.236/lb) for feedstock soybean oil, a biodiesel production cost of US dollar 0.53/l (dollar 2.00/gal) was predicted. The single greatest contributor to this value was the cost of the oil feedstock, which accounted for 88% of total estimated production costs. An analysis of the dependence of production costs on the cost of the feedstock indicated a direct linear relationship between the two, with a change of US dollar 0.020/l (dollar 0.075/gal) in product cost per US dollar 0.022/kg (dollar 0.01/lb) change in oil cost. Process economics included the recovery of coproduct glycerol generated during biodiesel production, and its sale into the commercial glycerol market as an 80% w/w aqueous solution, which reduced production costs by approximately 6%. The production cost of biodiesel was found to vary inversely and linearly with variations in the market value of glycerol, increasing by US dollar 0.0022/l (dollar 0.0085/gal) for every US dollar 0.022/kg (dollar 0.01/lb) reduction in glycerol value. The model is flexible in that it can be modified to calculate the effects on capital and production costs of changes in feedstock cost, changes in the type of feedstock employed, changes in the value of the glycerol coproduct, and changes in process chemistry and technology.

Sequencing batch reactor technology: the key to a BP refinery (Bulwer Island) upgraded environmental protection system--a low cost lagoon based retro-fit.

BP Refinery (Bulwer Island) Ltd (BP) located on the eastern Australian coast is currently undergoing a major expansion as a part of the Queensland Clean Fuels Project. The associated wastewater treatment plant upgrade will provide a better quality of treated effluent than is currently possible with the existing infrastructure, and which will be of a sufficiently high standard to meet not only the requirements of imposed environmental legislation but also BP's environmental objectives. A number of challenges were faced when considering the upgrade, particularly; cost constraints and limited plot space, highly variable wastewater, toxicity issues, and limited hydraulic head. Sequencing Batch Reactor (SBR) Technology was chosen for the lagoon upgrade based on the following; SBR technology allowed a retro-fit of the existing earthen lagoon without the need for any additional substantial concrete structures, a dual lagoon system allowed partial treatment of wastewaters during construction, SBRs give substantial process flexibility, SBRs have the ability to easily modify process parameters without any physical modifications, and significant cost benefits. This paper presents the background to this application, an outline of laboratory studies carried out on the wastewater and details the full scale design issues and methods for providing a cost effective, efficient treatment system using the existing lagoon system.

The SBR process: an efficient and economic solution for the treatment of wastewater at small cheesemaking dairies in the Jura mountains.

The small cheesemaking plants in the Jura Mountains (N.E. France) need self-contained solutions for treating their wastewater. Any solution must suit the characteristics of the effluent produced by these small production units and be simple, robust and financially feasible in regard to both capital and running costs. Given this context, a technique based on an SBR was recommended and the operations of the first treatment plant established on an industrial scale, monitored for the first year, with particular attention paid to operating constraints. The results obtained show that the SBR is, from a technical point of view, perfectly adapted to treating cheese production wastewater, with purification levels at 97.7% for total COD and 99.8% for BOD5. In the course of this study, it has been shown that the SBR process, thanks to its simple design and operation, can easily be run by the cheesemaker who will need to devote a minimum of time to it. Furthermore, with treatment costs of around 2 centimes (0.33 US cent) per litre of milk delivered, the SBR process meets perfectly both the technical and financial conditions for treatment as laid down by the Federation of Cooperatives of the Doubs and Jura départements.