Products Of Commercial Value Research Articles

A Comprehensive Analysis of Apricot Drying Methods via Multi‐Criteria Decision Making Techniques

ABSTRACTFood and food safety have been among the most important issues for people throughout history. Societies have always tried to be self‐sufficient in food and have avoided becoming dependent on foreign sources. However, the fact that most foods are seasonal and the increasing population's food consumption have revealed the need to preserve foodstuffs for a long time. The old and well‐known method used today for extending shelf life is the drying process. The drying process is preferred over other preservation methods for reasons such as being more economical, easier to transport, having a longer shelf life, more concentrated nutritional value, and containing fewer additives. This ensures that dried foods are of higher quality in terms of physical, chemical, microbial properties, and nutritional values compared to other packaged foods. While the drying process was traditionally done over a long period, technological advancements have led to the production of higher quality and more valuable commercial products in a shorter time. In this study, traditional and technological methods used in drying apricots were compared according to the parameters determined by experts in the field. Since multiple parameters are effective in the comparison, Multi‐Criteria Decision Making (MCDM) techniques were used. The optimum apricot drying method was determined by combining the results obtained from different MCDM techniques with the Borda rule.

Extracellular Endoglucanase and Exoglucanase Enzymes Production by Trichoderma viride Utilizing Olive Mill Wastewater (OMW) in liquid fermentation

Background:The cellulase enzyme is one of the most industrially important enzymes. Its cost represents a significant barrier to other valuable commercial products. Reducing the cost of cellulase production is an important approach. Objectives: For this purpose, this work investigated the production of cellulase enzyme using olive oil production waste (olive mill wastewater (OMW). Materials and methods: The ability of Trichoderma viride to utilize OMW as a substrate for cellulase production was studied. Optimization of cellulase production was investigated to find out the optimum OMW concentration, agitation speed, aeration rate, and cellulose addition. Results:The results showed that 75% v/v OMW submerged shake flask culture was the most suitable culture for T. viride growth and cellulase enzyme production (0.82 U/ml endoglucanase activity and 0.25 U/ml exoglucanase activity). When this culture was supplemented with cellulose, the activity of endoglucanase and exoglucanase was significantly improved (10.24 U/ml and 2.17 U/ml respectively).The agitation speed of 200 rpm enhanced the production to reach 9.1 U/ml of endoglucanase and 6.38 U/ml of exoglucanase. The effect of the aeration rate on enzyme production was studied under batch cultivation. The highest cellulase activity was at 2.0 vvm, where the endoglucanase and exoglucanase activities were 55.96 U/ml and 32.62 U/ml respectively. Conclusions: Therefore, it is claimed that OMW is a suitable medium for cellulase enzyme production after optimization of the process.

Novel resource-efficient recovery of high purity indium products: Unlocking value from end-of-life mobile phone liquid crystal display screens

Liquid crystal display (LCD) screens found in most electrical and electronic equipment consume approximately 75% of the total indium produced globally. Due to indium’s unique properties and applications, the escalation in demand for the metal and the threat to supply of the metal, mined primarily as a by-product of zinc production, are critical. To mitigate these challenges the need to recover indium from end-of-life (EoL) products is becoming an imperative. In this work, EoL mobile phones (EoL-MPs), which represent a resource-rich stream for critical metals in general, and, specifically indium from LCDs, are used as a feedstock. Using a simulated Model Test System, with the task-specific ionic liquid, Cyphos 101, the optimal conditions for recovery of indium are determined before application to real samples. A complete hydrometallurgical process was developed for the recovery of indium from as-received EoL-MP LCDs as a four-step process involving pre-treatment, liquid-liquid extraction, elution and reduction, using the task-specific IL, Cyphos 101, as extractant. This novel hydrometallurgical process developed can achieve overall efficiencies of ≥ 90% for indium recovery in the form of two high-purity (≥ 99%) indium products of commercial value and offers a promising approach for recovery from any e-waste stream rich in indium. Moreover, this low energy process permits the reuse of the IL up to five consecutive times and has the potential to unlock value as polymeric films, glass substrate and liquid crystal for recycle and reuse within the circular economy.

Complementary chromatic adaptation as a strategy to increase energy conversion efficiency of microalgae-cyanobacteria consortia in continuous LED photobioreactors

Phototrophic cultivation of microalgae represents a potential sustainable process to obtain valuable commercial products, but the industrial cultivation is still hampered by low energy-to-biomass conversion efficiency. However, a number of cyanobacteria species evolved the ability to adapt to the prevailing light spectrum exploiting phycobiliproteins and Complementary Chromatic Adaptation (CCA). Spectral properties of such accessory pigments can be, hence, used to cover the green gap and possibly use light energy more efficiently. In this work, the green microalgae Tetradesmus obliquus and the chromatically adapting cyanobacterium Tolypothrix tenuis were cultivated as an alga-alga consortium in chemostat, aimed at increasing the light utilization efficiency in LEDs illuminated photobioreactors. When grown in co-culture, the advantage of consortium, with respect to monocultures, was maintained under different spectra, achieving an areal productivity up to 38 g m−2 d−1 under low red light. A remarkable photosynthetic conversion efficiency was reached under cocultivation, as a result of a wider absorption of photons with different wavelengths by the two species. Red light also resulted the most suitable one from the overall energy balance when artificial light is used. In this condition, by also considering the lamp efficiency, an overall conversion efficiency equal to 21% was reached (on Photosynthetically Active Radiations of RED light and calculated for the biomass of the two species together). The consortium performances were preliminary evaluated in continuous photobioreactors at pilot scale in 16 L and 160 L reactors, confirming the results obtained at lab scale. Hence, we found that is possible to efficiently convert light energy supplied to photobioreactors through a rationale use of light and widening wavelengths absorption spectrum thanks to co-existing species. Such results indicate that innovative consortia establishment can be advantageous for future research and industrial microalgae cultivation.

Lethality Validation for Human Pathogenic Salmonella enterica on Chicken Feathers and Blood during Simulated Commercial Low-Temperature Dry Rendering.

Poultry rendering is the process of upcycling inedible poultry carcass materials into useful animal food/feed components as well as other valuable commercial products. Microbiological safety validation is nonetheless critical to ensuring the prevention of food safety hazard(s) transmission. This study determined the death kinetics of the thermotolerant Salmonella enterica serovar Senftenberg isolate 775W in chicken feathers and blood in low-temperature dry rendering (i.e., no direct contact with heating medium) to validate pathogen inactivation in commercial processing. Chicken feathers and blood were inoculated with Salmonella Senftenberg 775W and heated to 60, 70, or 80 °C for up to 60, 20, and 5 min, respectively. Three identically completed replicates (N = 3) for each product were conducted. Pathogen inactivation data were fitted to a non-linear model, providing for the detection and characterization of shoulder, log-linear death, and tailing components in death curves. The analysis showed a >7-log10 reduction in Salmonella was achieved across all processing temperatures, with t7D values (time for 7.0 log-cycle lethality) ranging from 21.68, 7.30, and 4.26 min for feathers and 18.38, 5.03, and 2.79 min in blood at 60, 70, and 80 °C, respectively. Study findings validate that low-temperature processing conditions can inactivate Salmonella in poultry-rendered offal.

Recycling of Chrome-Containing Waste from a Mining and Processing Plant to Produce Industrial Products

Prolonged development of ore deposits, ore beneficiation and metallurgical smelting of concentrates result in the accumulation of wastes, forming large-scale dumps and sludge ponds negatively affecting the environment and human health. The creation and introduction of industrial waste treatment technologies will make it possible to dispose of them with the production of valuable commercial products and improve the environmental situation. In a research article on chemical beneficiation with the subsequent gravitational beneficiation of chrome-containing slurry tailings of Donskoy Ore-Mining and Beneficiation Plant (DOMBP), which processes chrome ore of the Kempirsay deposit in the Republic of Kazakhstan, Aktobe region, having considerable stocks of such waste is presented. The chromium-containing slurry tailings were heat-treated at 1100 °C, sintered with ammonium sulfate, water and sulfuric acid in a defined ratio at 300 °C, and then the resulting sinter was leached with water at 90 °C. The cake was washed to separate the liquid part from the solid part. The solid precipitate is the chromium-containing cake, which is upgraded by gravity concentration to a grade concentrate for ferroalloy production. When the solution is evaporated, magnesium sulfate with ammonium sulfate forms the Tutton’s salt ammoshenite. High-throughput chromium oxide extraction of 93.9% was achieved as a result of the research, and three products were obtained: (1) standard chromium concentrate with 49.48% Cr2O3 content, (2) ammoshenite used as a nitrogen–magnesium fertilizer and (3) forsterite, which is concentrated in gravity concentration tailings and can be used in the production of refractory minerals.

Novel 15N Metabolic Labeling-Based Large-Scale Absolute Quantitative Proteomics Method for Corynebacterium glutamicum.

With fast growth, synthetic biology powers us with the capability to produce high commercial value products in an efficient resource/energy-consuming manner. Comprehensive knowledge of the protein regulatory network of a bacterial host chassis, e.g., the actual amount of the given proteins, is the key to building cell factories for certain target hyperproduction. Many talent methods have been introduced for absolute quantitative proteomics. However, for most cases, a set of reference peptides with isotopic labeling (e.g., SIL, AQUA, QconCAT) or a set of reference proteins (e.g., commercial UPS2 kit) needs to be prepared. The higher cost hinders these methods for large sample research. In this work, we proposed a novel metabolic labeling-based absolute quantification approach (termed nMAQ). The reference Corynebacterium glutamicum strain is metabolically labeled with 15N, and a set of endogenous anchor proteins of the reference proteome is quantified by chemically synthesized light (14N) peptides. The prequantified reference proteome was then utilized as an internal standard (IS) and spiked into the target (14N) samples. SWATH-MS analysis is performed to obtain the absolute expression levels of the proteins from the target cells. The cost for nMAQ is estimated to be less than 10 dollars per sample. We have benchmarked the quantitative performance of the novel method. We believe this method will help with the deep understanding of the intrinsic regulatory mechanism of C. glutamicum during bioengineering and will promote the process of building cell factories for synthetic biology.

Evaluation of Agave tequilana by-products for microbial production of hyaluronic acid

The tequila industry generates enormous amounts of solid byproducts originated from the agave plant such as leaves (AL) and bagasse (AB). Agave leaves are often left on the fields for natural degradation and agave bagasse is usually burned. An ideal option for the use of these residues is obtaining high commercial value products such as hyaluronic acid (HA). In this contribution the production of HA with Streptococcus zooepidemicus was evaluated using the juice from AL, and with enzymatic hydrolyzates. The hydrolyzates were produced from untreated fibers from both AB and AL and acid-pretreated fiber from AB and AL. The juice obtained from AL had the highest amounts of monosaccharides (42.05 g/L). However, a higher production of HA (4.23 g/L) was obtained from hydrolyzates of pretreated fibers from AL. This research shows that residues from tequila industry are a promising source of monosaccharides for production of hyaluronic acid with Streptococcus zooepidemicus.

New Synthetic Operon Vectors for Expressing Multiple Proteins in the Chlamydomonas reinhardtii Chloroplast.

Microalgae are a promising platform for generating valuable commercial products, including proteins that may not express well in more traditional cell culture systems. In the model green alga Chlamydomonas reinhardtii, transgenic proteins can be expressed from either the nuclear or chloroplast genome. Expression in the chloroplast has several advantages, but technology is not yet well developed for expressing multiple transgenic proteins simultaneously. Here, we developed new synthetic operon vectors to express multiple proteins from a single chloroplast transcription unit. We modified an existing chloroplast expression vector to contain intercistronic elements derived from cyanobacterial and tobacco operons and tested the ability of the resulting operon vectors to express two or three different proteins at a time. All operons containing two of the coding sequences (for C. reinhardtii FBP1 and atpB) expressed the products of those genes, but operons containing the other two coding sequences (C. reinhardtii FBA1 and the synthetic camelid antibody gene VHH) did not. These results expand the repertoire of intercistronic spacers that can function in the C. reinhardtii chloroplast, but they also suggest that some coding sequences do not function well in the context of synthetic operons in this alga.

Lignocellulose Biomass Liquefaction: Process and Applications Development as Polyurethane Foams.

One of the main strategies for sustainable human society progress is the development of efficient strategies to limit waste production and maximize renewable resource utilization. In this context, this review highlights the opportunity to transform vegetable biomass residues into valuable commercial products. Biomass conversion entails the depolymerization of lignocellulosic biomass towards biopolyols and the synthesis and characterization of the valuable products obtained by using them. The influence of the reaction parameters in both acid and basic catalysis is highlighted, respectively the influence of microwaves on the liquefaction reaction versus conventional heating. Following the depolymerization reaction, polyols are employed to produce polyurethane foams. As a special characteristic, the addition of flame-retardant properties was emphasized. Another interesting topic is the biodegradability of these products, considering the negative consequences that waste accumulation has on the environment.

Innovation from waste with biomass-derived chitin and chitosan as green and sustainable polymer: A review

The need for developing renewable materials to reduce the reliance on fossil fuels as a feedstock for a wide variety of uses is becoming increasingly widely acknowledged in society. Chitin, the second most abundant nitrogenous natural polymer derived from renewable biomass resources, have attracted significant interest as a promising natural source to produce functional materials due to their unique properties, abundant availability, and environmental appeal. Chitin is present in huge amounts in seafood waste, which is severely underutilized, resulting in resource wastage. An appealing alternative is to upcycle chitin-containing trash into value-added goods, to meet the sustainable development requirements. Since the large quantities of seafood waste remain underexploited, their utilization can potentially bring both ecological and economic benefits. The present review discusses the general properties of chitin and chitosan as natural polysaccharides, highlighting the innovative and eco-friendly methods for recovery of chitin and its derivatives from waste sources. The recent trends of the application of chitin and chitosan in various sectors are explored, highlighting the nexus between the generation and management of seafood waste and its transformation into valuable commercial products as a solution.

Exergetic Assessment of Waste Gas to Energy in a Novel Integrated NGL Recovery and Power Generation Plant

Natural gas processing, as one of the major energy sources, has become a focal point in boosting the energy value chain by processing high commercial value products such as natural gas liquids (NGL) and electricity generation. Natural gas processing has also amplified its usefulness to human well-being and global prosperity in different ways. However, the spate of gas flaring is a global phenomenon, despite advances in waste gas management technology. This research describes a unique integrated plant that recovers NGL and produces electricity via waste gas for the energy conversion process. Exergetic analysis has been offered to identify the causes of irreversibilities in the plant. Simulation models were built using the AspenOne HYSYS V10 and Aspen Plus V10 software to conceptualize the plant. The recovery of 60 kBD NGL and 2.55 kg mol/s of 97% lean methane gas (95% purity) as the residue was achieved from 320 MMSCFD of waste gas processing. The residue methane gas is combusted in a combustion chamber to recover hot gas in a heat recovery steam generator (HRSG) for steam generation and production of 646 MW of electricity. Analysis revealed that the heat exchangers collectively accounted for about 78% exergy destruction in the NGL recovery plant, while the 3 and 1.54%, respectively, of exergy is destroyed and lost in the demethanizer. The steam power plant showed similar irreversibilities with the boiler exchanger accounting for up to 88% exergy destruction. About 1.4% of exergy is lost as flue gas to the environment. At optimization, overall exergy efficiency reached 77.5 and 80.6% in the NGL recovery and steam power plant, respectively. Thus, this integrated plant model has not only demonstrated a marked improvement to similar models but is also a lucrative alternative to waste flare gas management. It is also proven to be a “flare-capture” alternative model for fossil fuels-related emission reduction and optimization tool for waste gas to energy.

Submarine groundwater discharge as a potential driver of eastern oyster, Crassostrea virginica, populations in Georgia

Reef-building eastern oysters, Crassostrea virginica, provide many ecosystem services, including production of valuable commercial products, formation of complex habitats, improved water quality and shoreline protection. Despite this, oyster populations have experienced dramatic declines throughout their range, spawning massive investment in management and restoration. Restoration efforts typically consider several well-studied metrics that normally influence oyster success; however, one potential factor that has not received much prior attention is submarine groundwater discharge (SGD). We conducted a series of field surveys and field experiments to explore the relationship between SGD and oysters in a marsh-lined tidal creek in Georgia, USA. SGD was mapped across multiple time points using a natural radon tracer (radon-222), and fluxes were paired with discrete measurements of oyster density, condition, size, recruitment and growth at multiple locations along the creek. Variation in oyster metrics was best explained by a combination of SGD, pH, and DO, which displayed a high degree of multicollinearity. We found an overall negative, nonlinear relationship between oyster density and groundwater flux. Interestingly, juvenile and adult condition and growth were not negatively impacted by groundwater. Rather, our results suggest that the likely mechanism for the density-flux relationship was interruption of the larval recruitment, which was also negatively related to flux. We hypothesize that larval interruption is due to the low dissolved oxygen and pH conditions of the groundwater at high flux sites. Overall, the interaction between SGD and oysters appears complex, and may be affected by other variables. This study provides evidence of a potential negative effect of a previously understudied natural phenomena on oyster demographics, and we suggest that SGD be considered in future management efforts.

Modeling of the process of collection, sorting and transportation of logging residues at the logging area

Effectiveness of economic development of logging industry is impossible without scientifically grounded strategies of formation of perspective technological logging processes with complex use of the total biomass of harvested trees. Degree of utilization of wood biomass is to be considered the most important principle of progressive logging technology. One of the main tasks of the national logging complex is the use of low-grade wood, lumpy wood waste, top of trees, twigs and branches, which will significantly improve efficiency of logging. To solve this problem, this article reviews the process of modeling of work of sorting and transportation machine designed for loading, sorting and transportation of felling residues to timber road. The technological scheme also provides cutting waste with knife for sorting by size. The study provides a detailed technological scheme of logging operations using forwarders with a removable body for loading, sorting and transportation of felling residues. The body of the forwarder is divided into compartments for transportation of waste with different parameters. The information and logical model of the process of collection, sorting and transportation of felling residue, which is proposed by machine, was offered. The formula for calculating the performance of operation of the sorting and transportation machine was obtained. Sorting according to species and types of felling residues is necessary for the production of fuel and technological wood chips for further use in production of valuable commercial products.

What we really know about the composition and function of microalgae cell coverings? - an overview

Cell coverings can be observed in all major groups of organisms, which include animals, plants, fungi, protists and prokaryotes. They play a key role in assuring cell survival or adaptation to certain environmental conditions. Since the term algae refers to a polyphyletic and very artificial group, the cell coverings of these organisms are very diverse in molecular composition and with different arrangements. Differences have taxonomic value since they allow microalgae phyla or even minor taxonomic groups, such as classes, orders or families, to be distinguished. Understanding the structure of cell coverings is also fundamental for the use of microalgae to obtain products of commercial value. Despite its importance, the composition and architecture of microalgae coverings is still poorly understood, especially considering the great diversity of organisms. Diatom frustules are the most studied coverings due their uses in areas of bio- and nanotechnology. There is a lack of information about the cell wall, lorica, periplast, amphiesma and scales. This study is a review with the aim of synthesizing literature information on microalgae cell coverings to describe their compositions, arrangements, functions and industrial uses.

Induction of root endosymbiosis as a highly sustainable and efficient strategy for overproduction of the medicinally important diterpenoid lactone-andrographolide in Andrographis paniculata (Burm. F.) Wall. ex Nees

Andrographis paniculata [(Burm. f.) Wall. ex Nees, family Acanthaceae], is an important medicinal plant used in Indian and Chinese traditional systems of medicines. The therapeutic activity of A. paniculata is due to the presence of andrographolide, a diterpenoid lactone with potent pharmacological activities. Andrographolide and its various semi synthetic derivatives are of high therapeutic potential and therefore of high demand. Due to the complex structure of andrographolide, chemical synthesis has not been effective till date and thus the pharmaceutical industry depends on A. paniculata for extraction of pure andrographolide. The content of andrographolide in A. paniculata is low (14.28 ± 1.62 mg/g DW) and thus biotechnological interventions are essential for enhanced production of andrographolide. The potential mutualistic role of endosymbiosis in enhancing the yield of andrographolide in in vitro cultures of A. paniculata was studied and the salient findings obtained are reported. It was consistently observed that colonization of roots of A. paniculata seedlings by the mutualistic endosymbiotic fungus Piriformospora indica resulted in significant enhancement of andrographolide (58.2 ± 6.5 mg/g DW) in comparison to control plants (19.5 ± 2.3 mg/g DW), along with a correlated increase in plant biomass. Fractions derived from P. indica such as cell wall and culture exudate were also employed to study their effect on andrographolide and biomass yield. It was observed that these fractions successfully improved the growth rate of the plant along with elevated andrographolide production, with maximum andrographolide content (55.8 ± 3.2 mg/g DW) observed in cell wall fraction treated seedlings. Under all the treatment conditions the transcriptional regulation of andrographolide biosynthetic pathway genes were analysed using RT-qPCR and correlated with andrographolide content. Andographolide biosynthesis pathway genes- GGPS, HMGS and DXR showed a significantly high transcript level expression and correlation with andrographolide accumulation over a period of 35 days in case of all the treatments studied. The potential protective role of P. indica colonization under host abiotic stress was demonstrated in A. paniculata seedlings exposed to abiotic stress conditions induced by poly ethylene glycol. Piriformospora indica colonized plants under drought stress exhibited normal morphology, high antioxidant enzyme content, low malondialdehyde accumulation and high proline content when compared with the control plants. The observations prove that P. indica and P. indica derived fractions can be used as an ideal bio stimulator to enhance the biomass (2.344 fold) and andrographolide content (3.91 fold) in A. paniculata. The findings also showed that as A. paniculata is significantly affected by drought stress, P. indica can also be used as a helpful eco-friendly tool to confer drought stress tolerance, thereby improving biomass and andrographolide yield. Moreover, the biostimulants present in the fungal cell wall fractions and culture exudates can be purified and characterized for exploring their further functional roles in order to develop products of commercial value.

Utilizing Food Waste Product (Date Tree Seeds) to Enhance the Filtration Characteristics in Water-Based Drilling Fluid System: A Comparative Study

AbstractPractically, to regulate filtration characteristics of drilling fluid, non-biodegradable materials used commonly have a high cost with side effects on personnel safety and the environment. Hence, eco-friendly additives are needed as an alternative to replace or at least support the commonly used filtration control agents. This experimental investigation examines the possibility of using date tree seeds’ powder (DTSP), as a new eco-friendly fluid loss agent. Under surface and sub-surface conditions (fresh and aged conditions), experiments were executed utilizing low-temperature and low-pressure (LTLP) and high-temperature and high-pressure (HTHP) American Petroleum Institute (API) filter press to comprehend the influence of DTSP on the seepage loss characteristics. The findings were compared with a commonly utilized chemical additive to regulate filtration characteristics of drilling fluid (low viscosity sodium carboxymethyl cellulose (CMC-LV)). Two concentrations of DTSP and CMC-LV were added separately to a reference fluid (RF) to understand the effect of concentration variations on filtration properties. The findings revealed that both DTSP and CMC-LV significantly improved the filtrate and the filter cake when comparing them with the RF under fresh and aged conditions. The findings for fresh conditions also showed that LTLP filtration measurements for CMC-LV additives had almost similar performance as DTSP additives, while HTHP filtration measurements exhibited that the two concentrations of DTSP additives were marginally better than those of CMC-LV additives. For aged conditions, CMC-LV additives were relatively more efficient than DTSP additives for LTLP filtration control experiments. However, DTSP additives were more efficient in improving the filtration characteristics as compared to CMC-LV additives for HTHP filtration control experiments. These results are in aid of shifting the oil and gas industry from using conventional harmful additives to using unconventional eco-friendly additives. This also helps in transforming unwanted food wastes into valuable commercial products, which can revolutionize the domestic and international industries and create new job opportunities, hence minimizing the total cost of drilling fluid and the wastes disposed to the environment.

Features of Zinc Extraction from Sulfide Forms

Zinc can be found in oxide and sulfide forms in technogenic formations. Zinc oxide extraction from technogenic formations is widely used in industry. Removing zinc sulfide from technogenic formations is difficult and is currently almost never used. In the present work, the physicochemical features of zinc extraction from sulfide are considered. Process thermodynamic features and possible ways to extract zinc sulfide are shown. Also, ways of valuable commercial products, obtaining from the roasting products, are considered.

Effect of trace metals on growth performance and accumulation of lipids, proteins, and carbohydrates on the green microalga Scenedesmus obliquus

Microalgae biomass is considered one of the most promising raw materials for the development of high commercial value products, mainly because they are potential sources of proteins, lipids, carbohydrates, and vitamins. In this way, the optimization of culture medium of these microorganisms can help to reduce production costs, making final products more accessible. In this sense, the present study aimed to investigate the effect of different trace metal concentrations on growth and biochemical composition of Scenedesmus obliquus. Cultures of S. obliquus were performed using the LCA-AD medium (pH 7.6), in 2-L cylindrical borosilicate glass flasks that were constantly stirred by bubbling 0.7% CO2 enriched air (v/v), irradiance ranging from 520 to 1200 μmols m−2 s−1, and temperature at 22 ± 1 °C. Four trace metal concentrations were tested: control (standard concentration used on Bold’s Basal Medium), ten (10−1), hundred (10−2), and thousand (10−3) times less than control. The trace metal concentration did not significantly affect the growth of S. obliquus – all treatments have reached about 4.2 g L−1 on the tenth day of cultivation. As well for growth performance, no significant differences were observed among the treatments for biomass composition percentages. The dry S. obliquus biomass was mainly composed of carbohydrates (about 65%), crude protein (about 20%), and finally lipids (about 12%). These findings suggest that up to 1000-fold reduction in trace metal concentration does not affect the growth and biochemical composition of the green microalga S. obliquus.

Molecular assays to detect the presence and viability of Phytophthora ramorum and Grosmannia clavigera

Wood and wood products can harbor microorganisms that can raise phytosanitary concerns in countries importing or exporting these products. To evaluate the efficacy of wood treatment on the survival of microorganisms of phytosanitary concern the method of choice is to grow microbes in petri dishes for subsequent identification. However, some plant pathogens are difficult or impossible to grow in axenic cultures. A molecular methodology capable of detecting living fungi and fungus-like organisms in situ can provide a solution. RNA represents the transcription of genes and can become rapidly unstable after cell death, providing a proxy measure of viability. We designed and used RNA-based molecular diagnostic assays targeting genes essential to vital processes and assessed their presence in wood colonized by fungi and oomycetes through reverse transcription and real-time polymerase chain reaction (PCR). A stability analysis was conducted by comparing the ratio of mRNA to gDNA over time following heat treatment of mycelial cultures of the Oomycete Phytophthora ramorum and the fungus Grosmannia clavigera. The real-time PCR results indicated that the DNA remained stable over a period of 10 days post treatment in heat-treated samples, whereas mRNA could not be detected after 24 hours for P. ramorum or 96 hours for G. clavigera. Therefore, this method provides a reliable way to evaluate the viability of these pathogens and offers a potential way to assess the effectiveness of existing and emerging wood treatments. This can have important phytosanitary impacts on assessing both timber and non-timber forest products of commercial value in international wood trade.