María Teresa Moreira

Understanding the factors controlling the removal of trace organic contaminants by white-rot fungi and their lignin modifying enzymes: A critical review

White-rot fungi (WRF) and their lignin modifying enzymes (LME) can degrade a wide range of trace organic contaminants (TrOC), which are suspected to cause adverse health effects in humans and other biota. Recent studies have successfully applied either whole-cell WRF or their extracellular culture extract to remove TrOC from the aqueous phase. TrOC removal by a WRF system is dependent on a range of factors including molecular structure of the TrOC, fungal species and their specific LME, culture medium composition, and methods to enhance fungal degradation capacity; however, the specific relationships between these factors have not been systematically delineated. The aim of this review paper is to fill this important gap in the literature by critically analysing the ability of WRF and their LME specifically to remove TrOC. Mechanisms and factors governing the degradation of TrOC by WRF and their LME are reviewed and discussed.

Benchmarking environmental and operational parameters through eco-efficiency criteria for dairy farms

Life Cycle Assessment (LCA) is often used for the environmental evaluation of agri-food systems due to its holistic perspective. In particular, the assessment of milk production at farm level requires the evaluation of multiple dairy farms to guarantee the representativeness of the study when a regional perspective is adopted. This article shows the joint implementation of LCA and Data Envelopment Analysis (DEA) in order to avoid the formulation of an average farm, therefore preventing standard deviations associated with the use of average inventory data while attaining the characterization and benchmarking of the operational and environmental performance of dairy farms. Within this framework, 72 farms located in Galicia (NW Spain) were subject to an LCA+DEA study which led to identify those farms with an efficient operation. Furthermore, target input consumption levels were benchmarked for each inefficient farm, and the corresponding target environmental impacts were calculated so that eco-efficiency criteria were verified. Thus, average reductions of up to 38% were found for input consumption levels, leading to impact reductions above 20% for every environmental impact category. Finally, the economic savings arising from efficient farming practices were also estimated. Economic savings of up to 0.13€ per liter of raw milk were calculated, which means extra profits of up to 40% of the final raw milk price.

Biobleaching of oxygen delignified kraft pulp by several white rot fungal strains

Twenty-five white rot fungal strains were tested for their ability to bleach Eucalyptus globulus oxygen delignified kraft pulp (OKP). Under nitrogen-limited culture conditions, eight outstanding biobleaching strains were identified that increased the brightness of OKP by more than 10 ISO units compared to pulp incubated in sterile control medium. The highest brightness gain of approximately 13 ISO units was obtained with Bjerkandera sp. strain BOS55, providing a high final brightness of 82% ISO. This strain also caused the greatest level of delignification, decreasing the kappa number of OKP by 29%. When the white rot fungal strains were tested in nitrogen-sufficient medium, the extracellular activities of laccase and peroxidases increased in many strains; nonetheless, the pulp handsheets were either destroyed or brightness gains were lower than those obtained under nitrogen-limitation. The titer of ligninolytic enzymes was not found to be indicative of biobleaching potential. However, the best biobleaching strains were generally characterized by a predominance of manganese dependent peroxidase (MnP) activity compared to other ligninolytic enzymes and by a high decolorizing activity towards the polyanthraquinone ligninolytic indicator dye, Poly R-478.

Further potentials in the joint implementation of life cycle assessment and data envelopment analysis

The combined application of Life Cycle Assessment and Data Envelopment Analysis has been recently proposed to provide a tool for the comprehensive assessment of the environmental and operational performance of multiple similar entities. Among the acknowledged advantages of LCA+DEA methodology, eco-efficiency verification and avoidance of average inventories are usually highlighted. However, given the novelty of LCA+DEA methods, a high number of additional potentials remain unexplored. In this sense, there are some features that are worth detailing given their wide interest to enhance LCA performance. Emphasis is laid on the improved interpretation of LCA results through the complementary use of DEA with respect to: (i) super-efficiency analysis to facilitate the selection of reference performers, (ii) inter- and intra-assessments of multiple data sets within any specific sector with benchmarking and trend analysis purposes, (iii) integration of an economic dimension in order to enrich sustainability assessments, and (iv) window analysis to evaluate environmental impact efficiency over a certain period of time. Furthermore, the capability of LCA+DEA methodology to be generally implemented in a wide range of scenarios is discussed. These further potentials are explained and demonstrated via the presentation of brief case studies based on real data sets.

Estimation of the carbon footprint of the Galician fishing activity (NW Spain).

The food production system as a whole is recognized as one of the major contributors to environmental impacts. Accordingly, food production, processing, transport and consumption account for a relevant portion of the greenhouse gas (GHG) emissions associated with any country. In this context, there is an increasing market demand for climate-relevant information regarding the global warming impact of consumer food products throughout the supply chains. This article deals with the assessment of the carbon footprint of seafood products as a key subgroup in the food sector. Galicia (NW Spain) was selected as a case study. The analysis is based on a representative set of species within the Galician fishing sector, including species obtained from coastal fishing (e.g. horse mackerel, Atlantic mackerel, European pilchard and blue whiting), offshore fishing (e.g. European hake, megrim and anglerfish), deep-sea fishing (skipjack and yellowfin tuna), extensive aquaculture (mussels) and intensive aquaculture (turbot). The carbon footprints associated with the production-related activities of each selected species were quantified following a business-to-business approach on the basis of 1year of fishing activity. These individual carbon footprints were used to calculate the carbon footprint for each of the different Galician fisheries and culture activities. Finally, the lump sum of the carbon footprints for coastal, offshore and deep-sea fishing and extensive and intensive aquaculture brought about the carbon footprint of the Galician fishing activity (i.e., capture and culture). A benchmark for quantifying and communicating emission reductions was then provided, and opportunities to reduce the GHG emissions associated with the Galician fishing activity could be prioritized.

Evaluation of forest operations in Spanish eucalypt plantations under a life cycle assessment perspective

Abstract The forest is an essential natural resource providing multiple benefits to people. However, forests face several environmental problems created by modern industrial society such as acidification, eutrophication and global warming. This study investigated the environmental loads associated with the Spanish forest sector, where this activity plays an important role in socioeconomic development. A Eucalyptus globulus plantation located in north-western Spain was considered as a case study. Forest operations were divided into three subsystems: silvicultural operations, logging operations and secondary hauling. The results showed that logging operations consume more energy than any other part of the wood supply chain, with a remarkable contribution in the potential impact categories of global warming, acidification and photochemical oxidant formation. Transportation of timber from forest landing to industrial sites (secondary hauling) is the second most important energy user. Silvicultural operations made an important contribution to eutrophication, mainly due to phosphorus-based fertilizer application. This study will enable improved Iberian life cycle assessment studies of wood products in the absence of detailed studies for this region.

Life cycle assessment of European pilchard (Sardina pilchardus) consumption. A case study for Galicia (NW Spain)

European pilchard or sardines (Sardina pilchardus) are an attractive raw material to extract from Iberian waters, since they constitute a cheap source of protein and they are a popular product among consumers. This has led to a wide range of final products available for consumers to purchase based on this single raw material. Therefore, this study presents a cross-product environmental assessment using life cycle assessment of three different final products based on sardine landings: canned sardines, fresh sardines and European hake caught by using sardine as bait. In addition, the products were followed throughout their entire life cycle, considering different cooking methods for each final product. Results showed high variability in environmental impacts, not only between the three final products, but also when one single product was cooked in different ways, highlighting the importance that the consumption phase and other post-landing stages may have on the final environmental profile of seafood. Results are then analysed regarding relevant limitations and uncertainties, as well as in terms of the consumer and policy implications.

Updating the carbon footprint of the Galician fishing activity (NW Spain)

Recent life cycle assessment studies have revealed the relevance of cooling agent leakage when assessing the greenhouse gas (GHG) emissions generated by fishing vessel operations. The goal of this communication is to update the carbon footprinting of the Galician fishing activity (NW Spain) by including the GHG emissions from cooling agent leakage. Results proved the relevant role played by refrigerants regarding their contribution to the carbon footprint of fishing activities. Thus, an overall increase of 13% was found when comparing the final global carbon footprint for the Galician fishing activity with previous calculations that did not include these emissions. Nevertheless, further efforts should be made in order to provide robust data in this respect.

Screening of white rot fungal species for their capacity to degrade lindane and other isomers of hexachlorocyclohexane (HCH)

J.C. Quintero, M.T. Moreira, G. Feijoo, and J.M. Lema. 2008. Screening of white rot fungal species for their capacity to degrade lindane and other isomers of hexachlorocyclohexane (HCH). Cien. Inv. Agr. 35(2):159-167. White-rot fungi have demonstrated a high capacity to degrade organic pollutants, including the insecticide lindane (γ-HCH). The purpose of this study γ was to evaluate the degradative capacities of several white rot fungi species, Bjerkandera adusta, Irpex lacteus, Lentinus tigrinus, Phanerochaete chrysosporium, Phanerochaete sordida, Phlebia radiata, Pleurotus eryngii, Poliporus cialatus, and Stereum hirsutum. Fungal tolerance to various concentrations of α-, β-, γ- and γ δ isomers of hexachlorocyclohexane (HCH) was studied in both liquid and soil media samples. δ- and γ-HCH isomers showed the highest inhibition of fungal γ growth of all HCH isomers. P. chrysosporium and B. adusta exhibited a high tolerance to HCH pollution. The δ- and γ-HCH isomers were degraded between 15.1 and 70.8% by six of the nine γ fungal species, B. adusta, P. ciliatus, L. tigrinu, S. hirsutum, P. eryngii, and I. lacteus; β-HCH was 56.6, 26.5 and 23.9% degraded by B. adusta, P. ciliatus and P. er yngii, respectively. In nonsterile soil, all the HCH isomers were degraded between 8.2 and 17.5% by B. adusta immobilized on corncobs or woodchips. In nonsterile soil, other soil microfl ora showed an antagonistic effect on white-rot fungi catalyzed degradation of HCH isomers.

Facile reduction of arsenate in methanogenic sludge

Due to the recent enactment of a stricter drinking water standard for arsenate, large quantities of arsenate-laden drinking water residuals will be disposed in municipal landfills. The objective of this study was to determine the role of methanogenic consortia on the conversion of arsenate. Methanogenic conditions commonly occur in mature municipal solid waste landfills. The results indicate the rapid and facile reduction of arsenate to arsenite in methanogenic sludge. Endogenous substrates in the sludge were sufficient to support the reductive biotransformation. However the rates of arsenate reduction were stimulated by the addition of exogenous electron donating substrates, such as H2, lactate or a mixture of volatile fatty acids. A selective methanogenic inhibitor stimulated arsenate reduction in microcosms supplied with H2, suggesting that methanogens competed with arsenate reducers for the electron donor. Rates of arsenate reduction increased with arsenate concentration up to 2 mM, higher concentrations were inhibitory. The electron shuttle, anthraquinone-2,6-disulfonate, used as a model of humic quinone moieties, was shown to significantly increase rates of arsenate reduction at substoichiometric concentrations. The presence of sulfur compounds, sulfate and sulfide, did not affect the rate of arsenate transformation but lowered the yield of soluble arsenite, due to the precipitation of arsenite with sulfides. The results taken as a whole suggest that arsenate disposed into anaerobic environments may readily be converted to arsenite increasing the mobility of arsenic. The extent of the increased mobility will depend on the concentration of sulfides generated from sulfate reduction.