Biotechnology-a sustainable alternative for chemical industry

Calorespirometric feeding control enhances bioproduction from toxic feedstocks-Demonstration for biopolymer production out of methanol

The sustainable production of fuels and industrial bulk chemicals by microorganisms in biotechnological processes is promising but still facing various challenges. In particular, toxic substrates require an efficient process control strategy. Methanol, as an example, has the potential to become a major future feedstock due to its availability from fossil and renewable resources. However, besides being toxic, methanol is highly volatile. To optimize its dosage during microbial cultivations, an innovative, predictive process control strategy based on calorespirometry, i.e., simultaneous measurements of heat and CO2 emission rates, was developed. This rarely used technique allows an online-estimation of growth parameters such as the specific growth rate and substrate consumption rate as well as a detection of shifts in microbial metabolism thus enabling an adapted feeding for different phases of growth. The calorespirometric control strategy is demonstrated exemplarily for growth of the methylotrophic bacterium Methylobacterium extorquens on methanol and compared to alternative control strategies. Applying the new approach, the methanol concentration could be maintained far below a critical limit, while increased growth rates of M. extorquens and higher final contents of the biopolymer polyhydroxybutyrate were obtained. Biotechnol. Bioeng. 2016;113: 2113-2121. © 2016 Wiley Periodicals, Inc.

Anoxic metabolism and biochemical production in Pseudomonas putida F1 driven by a bioelectrochemical system

BACKGROUND

Pseudomonas putida is a promising host for the bioproduction of chemicals, but its industrial applications are significantly limited by its obligate aerobic character. The aim of this paper is to empower the anoxic metabolism of wild-type Pseudomonas putida to enable bioproduction anaerobically, with the redox power from a bioelectrochemical system (BES).

RESULTS

The obligate aerobe Pseudomonas putida F1 was able to survive and produce almost exclusively 2-Keto-gluconate from glucose under anoxic conditions due to redox balancing with electron mediators in a BES. 2-Keto-gluconate, a precursor for industrial anti-oxidant production, was produced at an overall carbon yield of over 90 % based on glucose. Seven different mediator compounds were tested, and only those with redox potential above 0.207 V (vs standard hydrogen electrode) showed interaction with the cells. The productivity increased with the increasing redox potential of the mediator, indicating this was a key factor affecting the anoxic production process. P. putida cells survived under anaerobic conditions, and limited biofilm formation could be observed on the anode's surface. Analysis of the intracellular pools of ATP, ADP and AMP showed that cells had an increased adenylate energy charge suggesting that cells were able to generate energy using the anode as terminal electron acceptor. The analysis of NAD(H) and NADP(H) showed that in the presence of specific extracellular electron acceptors, the NADP(H) pool was more oxidised, while the NAD(H) pool was unchanged. This implies a growth limitation under anaerobic conditions due to a shortage of NADPH and provides a way to limit biomass formation, while allowing cell maintenance and catalysis at high purity and yield.

CONCLUSIONS

For the first time, this study proved the principle that a BES-driven bioconversion of glucose can be achieved for a wild-type obligate aerobe. This non-growth bioconversion was in high yields, high purity and also could deliver the necessary metabolic energy for cell maintenance. By combining this approach with metabolic engineering strategies, this could prove to be a powerful new way to produce bio-chemicals and fuels from renewables in both high yield and high purity.

Production of medium-chain carboxylic acids by Megasphaera sp. MH with supplemental electron acceptors

BACKGROUND

C5-C8 medium-chain carboxylic acids are valuable chemicals as the precursors of various chemicals and transport fuels. However, only a few strict anaerobes have been discovered to produce them and their production is limited to low concentrations because of product toxicity. Therefore, a bacterial strain capable of producing high-titer C5-C8 carboxylic acids was strategically isolated and characterized for production of medium chain length carboxylic acids.

RESULTS

Hexanoic acid-producing anaerobes were isolated from the inner surface of a cattle rumen sample. One of the isolates, displaying the highest hexanoic acid production, was identified as Megasphaera sp. MH according to 16S rRNA gene sequence analysis. Megasphaera sp. MH metabolizes fructose and produces various medium-chain carboxylic acids, including hexanoic acid, in low concentrations. The addition of acetate to the fructose medium as an electron acceptor increased hexanoic acid production as well as cell growth. Supplementation of propionate and butyrate into the medium also enhanced the production of C5-C8 medium-chain carboxylic acids. Megasphaera sp. MH produced 5.7 g L(-1) of pentanoic acid (C5), 9.7 g L(-1) of hexanoic acid (C6), 3.2 g L(-1) of heptanoic acid (C7) and 1.2 g L(-1) of octanoic acid (C8) in medium supplemented with C2-C6 carboxylic acids as the electron acceptors. This is the first report on the production of high-titer heptanoic acid and octanoic acid using a pure anaerobic culture.

CONCLUSION

Megasphaera sp. MH metabolized fructose for the production of C2-C8 carbon-chain carboxylic acids using various electron acceptors and achieved a high-titer of 9.7 g L(-1) and fast productivity of 0.41 g L(-1) h(-1) for hexanoic acid. However, further metabolic activities of Megaspahera sp. MH for C5-C8 carboxylic acids production must be deciphered and improved for industrially relevant production levels.

Algal remediation of CO₂ and nutrient discharges: A review

The recent literature pertaining to the application of algal photobioreactors (PBRs) to both carbon dioxide mitigation and nutrient abatement is reviewed and the reported data analysed. The review appraises the influence of key system parameters on performance with reference to (a) the absorption and biological fixation of CO2 from gaseous effluent streams, and (b) the removal of nutrients from wastewaters. Key parameters appraised individually with reference to CO2 removal comprise algal speciation, light intensity, mass transfer, gas and hydraulic residence time, pollutant (CO2 and nutrient) loading, biochemical and chemical stoichiometry (including pH), and temperature. Nutrient removal has been assessed with reference to hydraulic residence time and reactor configuration, along with C:nutrient ratios and other factors affecting carbon fixation, and outcomes compared with those reported for classical biological nutrient removal (BNR). Outcomes of the review indicate there has been a disproportionate increase in algal PBR research outputs over the past 5-8 years, with a significant number of studies based on small, bench-scale systems. The quantitative impacts of light intensity and loading on CO2 uptake are highly dependent on the algal species, and also affected by solution chemical conditions such as temperature and pH. Calculations based on available data for biomass growth rates indicate that a reactor CO2 residence time of around 4 h is required for significant CO2 removal. Nutrient removal data indicate residence times of 2-5 days are required for significant nutrient removal, compared with <12 h for a BNR plant. Moreover, the shallow depth of the simplest PBR configuration (the high rate algal pond, HRAP) means that its footprint is at least two orders of magnitude greater than a classical BNR plant. It is concluded that the combined carbon capture/nutrient removal process relies on optimisation of a number of process parameters acting synergistically, principally microalgal strain, C:N:P load and balance, CO2 and liquid residence time, light intensity and quality, temperature, and reactor configuration. This imposes a significant challenge to the overall process control which has yet to be fully addressed.

Stereoselective Bioreduction of α-Azido Ketones by Whole Cells of Marine-Derived Fungi

Seven strains of marine-derived fungi (Aspergillus sclerotiorum CBMAI 849, Cladosporium cladosporioides CBMAI 857, Penicillium raistrickii CBMAI 931, Penicillium citrinum CBMA 1186, Mucor racemosus CBMAI 847, Beauveria felina CBMAI 738, and Penicillium oxalicum CBMAI 1185) and terrestrial fungus Penicillium chrysogenum CBMA1199 were screened as catalysts for the asymmetric reduction of α-keto azides 5-8 to their corresponding β-azidophenylethanols 9-12. The marine fungi showed Prelog and anti-Prelog selectivities to the reduction α-keto azides 5-8. The fungi A. sclerotiorum CBMAI 849, C. cladosporioides CBMAI 857, P. raistrickii CBMAI 931, and P. citrinum CBMA 1186 catalyzed the reduction of azido ketone 6 to the corresponding (R)-2-azido-1-(4-methoxyphenyl)ethanol (10) with good conversions (68-100 %) and excellent enantiomeric excesses (>99 % ee) according to Prelog rule.

Converging sustainability definitions: industry independent dimensions

Purpose

– Sustainability as a construct is still debated and is yet to attain a consensus among researchers and practitioners. Sustainable development has been seen differently by players from different industry sectors. There is need to understand the commonality prevailing on sustainability practices across different industry sectors to arrive at a consensual sustainability definition. The purpose of this paper is to propose four dimensions of sustainability and studies how it captures sustainability practices across key industrial sectors.

Design/methodology/approach

– Current study argues the case for sustainability using four constructs, namely, economical, environmental, ethical, and social. Subsequently a holistic definition with a model is proposed incorporating the four constructs for sustainability. Studies documenting sustainability practices across industries, namely, automobile, infrastructure, cement and concrete, electronics, mining, paper, pharmaceutical, and logistics were reviewed to validate the applicability of the proposed four construct model across different key industrial sectors.

Findings

– Current study validates the industry independence of the proposed four constructs of sustainability model through a literature review. Very few studies have documented industry-specific sustainability practices and much lesser have studied the ethical dimension of sustainability. Furthermore, the organizational strategic plan is developed for incorporating the environmental, economical, ethical, and social needs into the organizational business operations at the strategic, tactical, and the operational levels.

Research limitations/implications

– Proposed model needs to be applied in multiple case organizations from diverse sectors to evaluate its capacity to capture the aspects of sustainability across different sectors. Future study could attempt to understand the interrelationships between the identified constructs and how they impact each other within different industrial sectors.

Practical implications

– Model linked to organizational business operations at the strategic, tactical, and the operational levels helps in the alignment of the organizational activity towards the strategic intent of the organizational sustainability philosophy in the business ecology. It also helps in equipping the organization to achieve the operational excellence and the strategic business growth at the same time.

Originality/value

– Current study is unique in its attempt to understand the capability of proposed sustainability dimensions to capture the sustainability practices followed across different industrial sectors.

Molecular Identification of a Newly Isolated Bacillus subtilis BI19 and Optimization of Production Conditions for Enhanced Production of Extracellular Amylase

A study was carried out with a newly isolated bacterial strain yielding extracellular amylase. The phylogenetic tree constructed on the basis of 16S rDNA gene sequences revealed this strain as clustered with the closest members of Bacillus sp. and identified as Bacillus subtilis BI19. The effect of various fermentation conditions on amylase production through shake-flask culture was investigated. Rice flour (1.25%) as a cheap natural carbon source was found to induce amylase production mostly. A combination of peptone and tryptone as organic and ammonium sulfate as inorganic nitrogen sources gave highest yield. Maximum production was obtained after 24 h of incubation at 37 °C with an initial medium pH 8.0. Addition of surfactants like Tween 80 (0.25 g/L) and sodium lauryl sulfate (0.2 g/L) resulted in 28% and 15% increase in enzyme production, respectively. Amylase production was 3.06 times higher when optimized production conditions were used. Optimum reaction temperature and pH for crude amylase activity were 50 °C and 6.0, respectively. The crude enzyme showed activity and stability over a fair range of temperature and pH. These results suggest that B. subtilis BI19 could be exploited for production of amylase at relatively low cost and time.

Suppressing the Neurospora crassa circadian clock while maintaining light responsiveness in continuous stirred tank reactors

Neurospora crassa has been utilized as a model organism for studying biological, regulatory, and circadian rhythms for over 50 years. These circadian cycles are driven at the molecular level by gene transcription events to prepare for environmental changes. N. crassa is typically found on woody biomass and is commonly studied on agar-containing medium which mimics its natural environment. We report a novel method for disrupting circadian gene transcription while maintaining light responsiveness in N. crassa when held in a steady metabolic state using bioreactors. The arrhythmic transcription of core circadian genes and downstream clock-controlled genes was observed in constant darkness (DD) as determined by reverse transcription-quantitative PCR (RT-qPCR). Nearly all core circadian clock genes were up-regulated upon exposure to light during 11hr light/dark cycle experiments under identical conditions. Our results demonstrate that the natural timing of the robust circadian clock in N. crassa can be disrupted in the dark when maintained in a consistent metabolic state. Thus, these data lead to a path for the production of industrial scale enzymes in the model system, N. crassa, by removing the endogenous negative feedback regulation by the circadian oscillator.

Scope of algae as third generation biofuels

An initiative has been taken to develop different solid, liquid, and gaseous biofuels as the alternative energy resources. The current research and technology based on the third generation biofuels derived from algal biomass have been considered as the best alternative bioresource that avoids the disadvantages of first and second generation biofuels. Algal biomass has been investigated for the implementation of economic conversion processes producing different biofuels such as biodiesel, bioethanol, biogas, biohydrogen, and other valuable co-products. In the present review, the recent findings and advance developments in algal biomass for improved biofuel production have been explored. This review discusses about the importance of the algal cell contents, various strategies for product formation through various conversion technologies, and its future scope as an energy security.

Identification of fungal ene-reductase activity by means of a functional screening

Bioeconomy stresses the need of green processes promoting the development of new methods for biocatalyzed alkene reductions. A functional screening of 28 fungi belonging to Ascomycota, Basidiomycota, and Zygomycota isolated from different habitats was performed to analyze their capability to reduce C=C double bonds towards three substrates (cyclohexenone, α-methylnitrostyrene, and α-methylcinnamaldehyde) with different electron-withdrawing groups, i.e., ketone, nitro, and aldehyde, respectively. Almost all the fungi showed this reducing activity. Noteworthy Gliomastix masseei, Mucor circinelloides, and Mucor plumbeus resulted versatile and effective, being able to reduce all the model substrates quickly and with high yields.

Electrolytic extraction drives volatile fatty acid chain elongation through lactic acid and replaces chemical pH control in thin stillage fermentation

BACKGROUND

Volatile fatty acids (VFA) are building blocks for the chemical industry. Sustainable, biological production is constrained by production and recovery costs, including the need for intensive pH correction. Membrane electrolysis has been developed as an in situ extraction technology tailored to the direct recovery of VFA from fermentation while stabilizing acidogenesis without caustic addition. A current applied across an anion exchange membrane reduces the fermentation broth (catholyte, water reduction: H2O + e(-) → ½ H2 + OH(-)) and drives carboxylate ions into a clean, concentrated VFA stream (anolyte, water oxidation: H2O → 2e(-) + 2 H(+) + O2).

RESULTS

In this study, we fermented thin stillage to generate a mixed VFA extract without chemical pH control. Membrane electrolysis (0.1 A, 3.22 ± 0.60 V) extracted 28 ± 6 % of carboxylates generated per day (on a carbon basis) and completely replaced caustic control of pH, with no impact on the total carboxylate production amount or rate. Hydrogen generated from the applied current shifted the fermentation outcome from predominantly C2 and C3 VFA (64 ± 3 % of the total VFA present in the control) to majority of C4 to C6 (70 ± 12 % in the experiment), with identical proportions in the VFA acid extract. A strain related to Megasphaera elsdenii (maximum abundance of 57 %), a bacteria capable of producing mid-chain VFA at a high rate, was enriched by the applied current, alongside a stable community of Lactobacillus spp. (10 %), enabling chain elongation of VFA through lactic acid. A conversion of 30 ± 5 % VFA produced per sCOD fed (60 ± 10 % of the reactive fraction) was achieved, with a 50 ± 6 % reduction in suspended solids likely by electro-coagulation.

CONCLUSIONS

VFA can be extracted directly from a fermentation broth by membrane electrolysis. The electrolytic water reduction products are utilized in the fermentation: OH(-) is used for pH control without added chemicals, and H2 is metabolized by species such as Megasphaera elsdenii to produce greater value, more reduced VFA. Electro-fermentation displays promise for generating added value chemical co-products from biorefinery sidestreams and wastes.

Biofuels from microalgae: lipid extraction and methane production from the residual biomass in a biorefinery approach

Renewable fuels and energy are of major concern worldwide and new raw materials and processes for its generation are being investigated. Among these raw materials, algae are a promising source of lipids and energy. Thus, in this work four different algae have been used for lipid extraction and biogas generation. Lipids were obtained by supercritical CO2 extraction (SCCO2), while anaerobic digestion of the lipid-exhausted algae biomass was used for biogas production. The extracted oil composition was analyzed (saturated, monounsaturated and polyunsaturated fatty acids) and quantified. The highest lipid yields were obtained from Tetraselmis sp. (11%) and Scenedesmus almeriensis (10%), while the highest methane production from the lipid-exhausted algae biomass corresponded to Tetraselmis sp. (236mLCH4/gVSadded).

Isolation and characterization of a Bacillus subtilis strain that degrades endosulfan and endosulfan sulfate

Endosulfan has emerged as a major environmental menace worldwide due to  extensive usage and environmental persistence, seeking its remedial by a cheaper and efficient means. Therefore, natural resource (soil) was explored to search a potential candidate for biodegradation of endosulfan. A soil bacterium was enriched and isolated by applying a strong nutritional selection pressure, using a non-sulfur medium supplemented with endosulfan as sole source sulfur. The microbial strain was found to degrade endosulfan as well as its equally toxic metabolite endosulfan sulfate to non-toxic metabolites (endodiol and endosulfan lactone) very efficiently (up to 94.2 %) within 7 days, estimated qualitatively by thin layer chromatography and quantitatively by gas chromatography-electron capture detection methods. The isolate was characterized for its morphological, physiological, biochemical and 16S rRNA sequencing and identified as a new strain of Bacillus subtilis with strain designation AKPJ04, which was deposited with accession number Microbial Type Culture Collection and Gene Bank (MTCC) 8561, at MTCC, Institute of Microbial Technology, Chandigarh, India. The partial 16S rRNA sequence was submitted to Genbank, Maryland, USA, with the accession number EU 258611. The primary investigation for endosulfan degrading gene(s) localization suggested its location on chromosomal DNA.

Biocapture of CO2 from biogas by oleaginous microalgae for improving methane content and simultaneously producing lipid

This study aimed to use oleaginous microalgae to capture CO2 from biogas for improving methane content and simultaneously producing lipid. Several microalgae were screened for their ability to grow and produce lipid using CO2 in biogas. A marine Chlorella sp. was the most suitable strain for capturing CO2 and producing lipid using biogas (50% v/v CO2 in methane) as well as using 50% v/v CO2 in air. The medium and operating conditions were optimized through response surface methodology (RSM). The optimal concentrations of KNO3 and K2HPO4 were 0.80gL(-1) and 0.06gL(-1), respectively. The optimal operating conditions were: initial pH of 7.8, initial cell concentration of 10(7.5)cellsmL(-1), light intensity of 4500lux and gas flow rate of 0.03Lmin(-1). After optimization, 89.3% of CO2 was removed from biogas and the methane content was increased up to 94.7%. The lipid productivity was 94.7mgL(-1)day(-1).

The influence of shear on the metabolite yield of Lactobacillus rhamnosus biofilms

A tubular recycle bioreactor was employed to ensure homogeneous shear conditions on the biofilm surface. Superficial liquid velocities of 0.19 ms(-1), 0.37 ms(-1), 0.55 ms(-1) and 3.65 ms(-1) were used. The highest velocity resulted in negligible cell attachment (chemostat) while the ratio of attached-to-total cell mass escalated as the superficial velocity decreased. The lactic acid yield on glucose increased from 0.75 g g(-1) to 0.90 g g(-1) with declining shear while the corresponding acetoin yield on glucose decreased from 0.074 g g(-1) to 0.017 g g(-1). Redox analysis of the catabolites revealed a net consumption of NADH in the anabolism, while the extent of NADH consumption decreased when shear was reduced. This was attributed to the formation of more extracellular polymeric substance (EPS) at low shear conditions. A simplified metabolic flux model was used to estimate the EPS content of the biomass as a function of the shear velocity. Rate data supported the notion of increased EPS at lower shear.

Nature's chemical signatures in human olfaction: a foodborne perspective for future biotechnology

The biocatalytic production of flavor naturals that determine chemosensory percepts of foods and beverages is an ever challenging target for academic and industrial research. Advances in chemical trace analysis and post-genomic progress at the chemistry-biology interface revealed odor qualities of nature's chemosensory entities to be defined by odorant-induced olfactory receptor activity patterns. Beyond traditional views, this review and meta-analysis now shows characteristic ratios of only about 3 to 40 genuine key odorants for each food, from a group of about 230 out of circa 10 000 food volatiles. This suggests the foodborn stimulus space has co-evolved with, and roughly match our circa 400 olfactory receptors as best natural agonists. This perspective gives insight into nature's chemical signatures of smell, provides the chemical odor codes of more than 220 food samples, and beyond addresses industrial implications for producing recombinants that fully reconstruct the natural odor signatures for use in flavors and fragrances, fully immersive interactive virtual environments, or humanoid bioelectronic noses.

Over-expression of Dof-type transcription factor increases lipid production in Chlamydomonas reinhardtii

The high demand for less polluting, newer, and cheaper fuel resources has increased the search of the most innovative options for the production of the so-called biofuels. Chlamydomonas reinhardtii is a photosynthetic unicellular algae with multiple biotechnological advantages such as easy handling in the laboratory, a simple scale-up to industrial levels, as well as a feasible genetic modification at nuclear and chloroplast levels. Besides, its fatty acids can be used to produce biofuels. Previous studies in plants have found that the over expression of DOF-type transcription factor genes increases the synthesis and the accumulation of total lipids in seeds. In this context, the over-expression of a DOF-type transcription factor in C. reinhardtii was applied as approach to increase the amount of lipids. The results indicate higher amounts (around 2-fold) of total lipids, which are mainly fatty acids, in the genetically C. reinhardtii modified strains when compared with the non-genetically modified strain. In order to elucidate the possible function of the introduced Dof-type transcription factor, we performed a transcription profile of 8 genes involved in fatty acid biosynthesis and 6 genes involved in glycerolipid biosynthesis, by quantitative real time (qRT-PCR). Differential expression profile was observed, which can explain the increase in lipid accumulation. However, these strains did not show notable changes in the fatty acid profile. This work represents an early effort in generating a strategy to increase fatty acids production in C. reinhardtii and their use in biofuel synthesis.

Integrated supply chain design for commodity chemicals production via woody biomass fast pyrolysis and upgrading

This study investigates the optimal supply chain design for commodity chemicals (BTX, etc.) production via woody biomass fast pyrolysis and hydroprocessing pathway. The locations and capacities of distributed preprocessing hubs and integrated biorefinery facilities are optimized with a mixed integer linear programming model. In this integrated supply chain system, decisions on the biomass chipping methods (roadside chipping vs. facility chipping) are also explored. The economic objective of the supply chain model is to maximize the profit for a 20-year chemicals production system. In addition to the economic objective, the model also incorporates an environmental objective of minimizing life cycle greenhouse gas emissions, analyzing the trade-off between the economic and environmental considerations. The capital cost, operating cost, and revenues for the biorefinery facilities are based on techno-economic analysis, and the proposed approach is illustrated through a case study of Minnesota, with Minneapolis-St. Paul serving as the chemicals distribution hub.

Microorganisms living on macroalgae: diversity, interactions, and biotechnological applications

Marine microorganisms play key roles in every marine ecological process, hence the growing interest in studying their populations and functions. Microbial communities on algae remain underexplored, however, despite their huge biodiversity and the fact that they differ markedly from those living freely in seawater. The study of this microbiota and of its relationships with algal hosts should provide crucial information for ecological investigations on algae and aquatic ecosystems. Furthermore, because these microorganisms interact with algae in multiple, complex ways, they constitute an interesting source of novel bioactive compounds with biotechnological potential, such as dehalogenases, antimicrobials, and alga-specific polysaccharidases (e.g., agarases, carrageenases, and alginate lyases). Here, to demonstrate the huge potential of alga-associated organisms and their metabolites in developing future biotechnological applications, we first describe the immense diversity and density of these microbial biofilms. We further describe their complex interactions with algae, leading to the production of specific bioactive compounds and hydrolytic enzymes of biotechnological interest. We end with a glance at their potential use in medical and industrial applications.

Emerging pollutants in the environment: present and future challenges in biomonitoring, ecological risks and bioremediation

Emerging pollutants reach the environment from various anthropogenic sources and are distributed throughout environmental matrices. Although great advances have been made in the detection and analysis of trace pollutants during recent decades, due to the continued development and refinement of specific techniques, a wide array of undetected contaminants of emerging environmental concern need to be identified and quantified in various environmental components and biological tissues. These pollutants may be mobile and persistent in air, water, soil, sediments and ecological receptors even at low concentrations. Robust data on their fate and behaviour in the environment, as well as on threats to ecological and human health, are still lacking. Moreover, the ecotoxicological significance of some emerging micropollutants remains largely unknown, because satisfactory data to determine their risk often do not exist. This paper discusses the fate, behaviour, (bio)monitoring, environmental and health risks associated with emerging chemical (pharmaceuticals, endocrine disruptors, hormones, toxins, among others) and biological (bacteria, viruses) micropollutants in soils, sediments, groundwater, industrial and municipal wastewaters, aquaculture effluents, and freshwater and marine ecosystems, and highlights new horizons for their (bio)removal. Our study aims to demonstrate the imperative need to boost research and innovation for new and cost-effective treatment technologies, in line with the uptake, mode of action and consequences of each emerging contaminant. We also address the topic of innovative tools for the evaluation of the effects of toxicity on human health and for the prediction of microbial availability and degradation in the environment. Additionally, we consider the development of (bio)sensors to perform environmental monitoring in real-time mode. This needs to address multiple species, along with a more effective exploitation of specialised microbes or enzymes capable of degrading endocrine disruptors and other micropollutants. In practical terms, the outcomes of these activities will build up the knowledge base and develop solutions to fill the significant innovation gap faced worldwide.

Carbon dioxide bio-fixation and wastewater treatment via algae photochemical synthesis for biofuels production

Utilizing the energy, nutrients and CO₂held within residual waste materials to provide all necessary inputs except for sunlight, the cultivation of algae becomes a closed-loop engineered ecosystem. Developing this green biotechnology is a tangible step towards a waste-free sustainable society.

Expression of fatty acid desaturase genes and fatty acid accumulation in Chlamydomonas sp. ICE-L under salt stress

The Antarctic ice microalgae Chlamydomonas sp. ICE-L which is highly resistant to salt stress holds promise in providing an alternative species for the production of microalgal oil. We studied the effects of the alga in confrontation with NaCl stress on the growth, oil yield and expression of fatty acid desaturase genes. The growth rate of Chlamydomonas sp. ICE-L decreased with the gradual increase in NaCl concentration. Interestingly, we found that the highest lipid content was achieved at 16‰ NaCl, reaching 23% (w/w). Meanwhile, the expression of Δ9ACPCiFAD increased rapidly while Δ12CiFAD, ω3CiFAD2 and Δ6CiFAD showed a delayed elevation in response to altered salt stress. C18:3 was the dominant PUFA, which account for about 75% TFA in Chlamydomonas sp. ICE-L. Under 96‰ and 128‰ NaCl stress, the content of C20:5 almost approached that of C18:3. In contrast, low salinity enhanced the dominance of C18:3 at the expense of C20:3 and C20:5.

Biosorption of heavy metals by Streptomyces species — an overview

Abstract Heavy metals, derived from industrial wastewater discharge, present a serious threat to human health and to natural water. Biosorption is regarded as a cost-effective biotechnology for the treatment of high volume and low concentration wastewaters containing heavy metal(s) in the order of 1 to 100 mg L−1. Among the biomaterials for heavy metal removal which have been researched during the past decades is the Streptomyces species, a by-product of an industrial antibiotic fermentation process. This paper describes the hazards posed by heavy metals effluents on the environment and use of various Streptomyces species to remove heavy metals from aqueous solution. Characterization of Streptomyces species, factors affecting biosorption, biosorption isotherms and biosorption kinetics is discussed. Graphical abstract

Production of biodiesel from microalgae Chlamydomonas polypyrenoideum grown on dairy industry wastewater

This study involves a process of phyco-remediation of dairy industry wastewater by algal strain Chlamydomonas polypyrenoideum. The results of selected algal strain indicated that dairy industry wastewater was good nutrient supplement for algal growth in comparable with BG-11 growth medium. Alga grown on dairy industry wastewater reduced the pollution load of nitrate (90%), nitrite (74%), phosphate (70%), chloride (61%), fluoride (58%), and ammonia (90%) on 10th day of its growth as compared to that of uninoculated wastewater. The lipid content of algal biomass grown on dairy wastewater on 10th day (1.6g) and 15th day (1.2 g) of batch experiment was found to be higher than the lipid content of algal biomass grown in BG-11 growth medium on 10th day (1.27 g) and 15th day (1.0 g) of batch experiment. The results on FTIR analysis of the extracted bio-oil through transesterification reaction was comparable with bio-oil obtained from other sources.

A methodological combined framework for roadmapping biosensor research: a fault tree analysis approach within a strategic technology evaluation frame

Biosensor technology began in the 1960s to revolutionize instrumentation and measurement. Despite the glucose sensor market success that revolutionized medical diagnostics, and artificial pancreas promise currently the approval stage, the industry is reluctant to capitalize on other relevant university-produced knowledge and innovation. On the other hand, the scientific literature is extensive and persisting, while the number of university-hosted biosensor groups is growing. Considering the limited marketability of biosensors compared to the available research output, the biosensor field has been used by the present authors as a suitable paradigm for developing a methodological combined framework for "roadmapping" university research output in this discipline. This framework adopts the basic principles of the Analytic Hierarchy Process (AHP), replacing the lower level of technology alternatives with internal barriers (drawbacks, limitations, disadvantages), modeled through fault tree analysis (FTA) relying on fuzzy reasoning to count for uncertainty. The proposed methodology is validated retrospectively using ion selective field effect transistor (ISFET) - based biosensors as a case example, and then implemented prospectively membrane biosensors, putting an emphasis on the manufacturability issues. The analysis performed the trajectory of membrane platforms differently than the available market roadmaps that, considering the vast industrial experience in tailoring and handling crystallic forms, suggest the technology path of biomimetic and synthetic materials. The results presented herein indicate that future trajectories lie along with nanotechnology, and especially nanofabrication and nano-bioinformatics, and focused, more on the science-path, that is, on controlling the natural process of self-assembly and the thermodynamics of bioelement-lipid interaction. This retained the nature-derived sensitivity of the biosensor platform, pointing out the differences between the scope of academic research and the market viewpoint.

Efficiency assessment and pH effect in removing nitrogen and phosphorus by algae-bacteria combined system of Chlorella vulgaris and Bacillus licheniformis

To achieve better removal of NH4(+) and TP in wastewater, a new algae-bacteria combined system of Chlorella vulgaris and Bacillus licheniformis was investigated in a 6-d experiment. The results showed that 78% of NH4(+) could be removed in the combined system, while 29% in single algae system and only 1% in single bacteria system. Approximately 92% of TP was removed in the combined system, compared with 55% and 78% in single algae and bacteria system, respectively. B. licheniformis was proven to be a growth-promoting bacterium for C. vulgaris by comparing Chl a concentrations in the single and combined systems. In the removal process, pH of the combined system was observed to reduce significantly from 7.0 to 3.5. Whereas with pH regulated to 7.0, higher removal efficiencies of NH4(+) (86%) and TP (93%) were achieved along with the recovery of algal cells and the increase of Chl a. These results suggest that nutrients in wastewater can be removed efficiently by the algae-bacteria combined system and pH control is crucial in the process.

Chitosan based heterogeneous catalyses: chitosan-grafted-poly(4-vinylpyridne) as an efficient catalyst for Michael additions and alkylpyridazinyl carbonitrile oxidation

Chitosan-grafted-poly(4-vinylpyridine) (Cs-PVP) copolymers could be synthesized under heterogeneous conditions in presence of a potassium persulfate and sodium sulfite redox system. The synthesized graft copolymer could be utilized effectively, in the form of beads, as an efficient catalyst for Michael additions of active methylenes to functionally substituted alkenes. Moreover, methyl moiety oxidation in methyl pyridazinyl carbonitriles by H₂O₂ in the presence of chitosan-g-polyvinyl pyridine–supported iron (III) complex, Cs-PVP/Fe, could be affected. A variety of pyrans, naphthopyrans, and thiopyrans could be synthesized efficiently in the presence of these graft copolymer beads by novel catalytic routes. These polymeric catalysts could be used instead of the old toxic commercial organic basic catalysts, piperidine or pyridine, and could be readily isolated from the reaction mixture and recycled several times without significant loss of catalytic activity.