Ethanol from sugarcane in Brazil: a ‘midway’ strategy for increasing ethanol production while maximizing environmental benefits

This article reviews the history and current state of ethanol production from sugarcane in Brazil and presents a strategy for improving ecosystem services and production. We propose that it is possible to produce ethanol from sugarcane while maintaining or even recovering some of Brazil's unique neotropical biodiversity and ecosystem climate services. This approach to the future of sustainable and responsible ethanol production is termed the ‘midway’ strategy. The ‘midway’ strategy involves producing the necessary biotechnology to increase productivity while synergistically protecting and regenerating rainforest. Three main areas of scientific and technological advance that are key to realizing the ‘midway’ strategy are: (i) improving the quality of scientific data on sugarcane biology as pertains to its use as a bioenergy crop; (ii) developing technologies for the use of bagasse for cellulosic ethanol; and (iii) developing policies to improve the ecosystem services associated with sugarcane landscapes. This article discusses these three issues in the general context of biofuels production and highlights examples of scientific achievements that are already leading towards the ‘midway’ strategy.     

红壤丘陵区粮食生产的生态成本

人类的生产活动必然对资源与环境造成影响,以红壤丘陵区的湖南省祁阳县为研究对象,应用经济学和生态学方法,对粮食生产中的生态成本进行了研究。结果表明:2008年该区粮食生产生态损失总价值相当于当年农业总产值的4.85%;早、中、晚稻生态成本已分别达到3.18、2.44、3.02元/kg,而出售单价分别为1.76、1.90、1.84元/kg,高成本低收益的情况对该区域的可持续发展产生着不利影响;在当前生产力水平条件下,适度提高化肥、农药、农业机械、农膜、劳动力的投入,提高水稻产量,扩大家庭种植规模,可降低生产单位水稻的生态成本。     

Biorefinery for combined production of jet fuel and ethanol from lipid‐producing sugarcane: a techno‐economic evaluation

Replacing fossil fuels with an economically viable green alternative at scale has proved most challenging in the aviation sector. Recently sugarcane, the most productive crop on the planet, has been engineered to accumulate lipids. This opens the way for production of far more industrial vegetable oil per acre than previously possible. This study performs techno‐economic feasibility analysis of jet fuel production from this new cost efficient and high yield feedstock. A comprehensive process model for biorefinery producing hydrotreated jet fuel (from lipids) and ethanol (from sugars), with 1 600 000 MT yr^?1 lipid‐cane processing capacity, was developed in SuperPro Designer. Considering lipid‐cane development is continuing for higher oil concentrations, analysis was performed with lipid‐cane containing 5%, 10%, 15%, and 20% lipids. Capital investments for the biorefinery ranged from 238.1 to 351.2 million USD, with jet fuel capacities of 12.6–50.5 million liters (correspondingly ethanol production of nil to 102.6 million liters). The production cost of jet fuel for different scenarios was estimated Replacing fossil fuels with an economically viable green alternative at scale has proved most challenging in the aviation sector. Recently sugarcane, the most productive crop on the planet, has been engineered to accumulate lipids. This opens the way for production of far more industrial vegetable oil per acre than previously possible. This study performs techno‐economic feasibility analysis of jet fuel production from this new cost efficient and high yield feedstock. A comprehensive process model for biorefinery producing hydrotreated jet fuel (from lipids) and ethanol (from sugars), with 1 600 000 MT yr^?1 lipid‐cane processing capacity, was developed in SuperPro Designer. Considering lipid‐cane development is continuing for higher oil concentrations, analysis was performed with lipid‐cane containing 5%, 10%, 15%, and 20% lipids. Capital investments for the biorefinery ranged from 238.1 to 351.2 million USD, with jet fuel capacities of 12.6–50.5 million liters (correspondingly ethanol production of nil to 102.6 million liters). The production cost of jet fuel for different scenarios was estimated $0.73 to $1.79 per liter ($2.74 to $6.76 per gal) of jet fuel. In all cases, the cost of raw materials accounted for more than 70% of total operational cost. Biorefinery was observed self‐sustainable for steam and electricity requirement, because of in‐house steam and electricity generation from burning of bagasse. Minimum fuel selling prices with a 10% discount rate for 20% lipid case was estimated $1.40/L ($5.31/gal), which was lower than most of the reported prices of renewable jet fuel produced from other oil crops and algae. Along with lower production costs, lipid‐cane could produce as high as 16 times the jet fuel (6307 L ha^?1) per unit land than that of other oil crops and do so using low‐value land unsuited to most other crops, while being highly water and nitrogen use efficient.     

Improving the fermentation performance of saccharomyces cerevisiae by laccase during ethanol production from steam‐exploded wheat straw at high‐substrate loadings

Operating the saccharification and fermentation processes at high‐substrate loadings is a key factor for making ethanol production from lignocellulosic biomass economically viable. However, increasing the substrate loading presents some disadvantages, including a higher concentration of inhibitors (furan derivatives, weak acids, and phenolic compounds) in the media, which negatively affect the fermentation performance. One strategy to eliminate soluble inhibitors is filtering and washing the pretreated material. In this study, it was observed that even if the material was previously washed, inhibitory compounds were released during the enzymatic hydrolysis step. Laccase enzymatic treatment was evaluated as a method to reduce these inhibitory effects. The laccase efficiency was analyzed in a presaccharification and simultaneous saccharification and fermentation process at high‐substrate loadings. Water‐insoluble solids fraction from steam‐exploded wheat straw was used as substrate and Saccharomyces cerevisiae as fermenting microorganism. Laccase supplementation reduced strongly the phenolic content in the media, without affecting weak acids and furan derivatives. This strategy resulted in an improved yeast performance during simultaneous saccharification and fermentation process, increasing significantly ethanol productivity. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013     

Spatial niche modelling of five endemic cacti from the Brazilian Caatinga: Past,present and future

Climate change, together with human activities, impacts on natural and human systems on all continents and poses a major threat to biodiversity, especially in environments with a high rate of endemism and where species are profoundly adapted to specific environmental conditions, as is the case of the seasonally dry tropical forests, noticeably the Caatinga, an exclusively Brazilian biome. The objective of this study was to build spatial niche models of five species of Cactaceae (Arrojadoa penicillata, Brasilicereus phaeacanthus, Pereskia aureiflora, Stephanocereus leucostele and Tacinga inamoena) endemic to the Caatinga and with different traits, to evaluate the impact of climate change on their geographical distribution. The species records and environmental variable values were overlaid on a grid of 6818 cells with 0.5° spatial resolution. Niche models were obtained for five types of general circulation models between ocean and atmosphere and 12 different ecological models. The ensemble ecological niche model was calculated at present and projected to past (last glacial maximum – LGM, 21 000; and mid‐Holocene – Hol, 6000 years ago) and future climate conditions (average of 2080), under the effect of climate change, in the greenhouse gas emission scenario RCP4.5. The distribution pattern of the studied species indicates an area with less environmental suitability in the LGM, followed by an expansion that began in the Hol and continued until the present period. In the future (2080), the models predicted a retraction of areas of environmental suitability, in which P. aureiflora and B. phaeacanthus, given their more restricted, marginal habitat and woody habit, present a great risk of extinction, whilst S. leucostele, A. penicillata and T. inamoena present a smaller reduction in suitable area, partly reflecting their spreading, less woody habit. Regional conservation actions for Cactaceae species and their habitat need to take these findings into account if we are to ensure the survival of these species.     

A decline in primary production in the North Sea over 25 years,associated with reductions in zooplankton abundance and fish stock recruitment

Phytoplankton primary production is at the base of the marine food web; changes in primary production have direct or indirect effects on higher trophic levels, from zooplankton organisms to marine mammals and seabirds. Here, we present a new time‐series on gross primary production in the North Sea, from 1988 to 2013, estimated using in situ measurements of chlorophyll and underwater light. This shows that recent decades have seen a significant decline in primary production in the North Sea. Moreover, primary production differs in magnitude between six hydrodynamic regions within the North Sea. Sea surface warming and reduced riverine nutrient inputs are found to be likely contributors to the declining levels of primary production. In turn, significant correlations are found between observed changes in primary production and the dynamics of higher trophic levels including (small) copepods and a standardized index of fish recruitment, averaged over seven stocks of high commercial significance in the North Sea. Given positive (bottom‐up) associations between primary production, zooplankton abundance and fish stock recruitment, this study provides strong evidence that if the decline in primary production continues, knock‐on effects upon the productivity of fisheries are to be expected unless these fisheries are managed effectively and cautiously.     

Sustainable Development and Cleaner Technology in Brazilian Energy CDM Projects: Consideration of Risks

Given the international urgency of addressing climate change, this article evaluates the contribution of energy Clean Development Mechanism (CDM) projects for the generation of cleaner technologies and the promotion of sustainable development in Brazil. In order to do this, energy CDM projects representing the Brazilian context were selected and a multi-case study was conducted. The data collected were compared using a data triangulation technique and further analyzed in the light of an analysis model built on the following concepts: CDM project's cycle, technology transfer, environmental technologies, and sustainable development. The results demonstrate the prevalence of projects that: (a) use renewable energy sources and technologies that can be classified as cleaner, (b) have a triple bottom line profile with regard to sustainable development, and (c) show partially exogenous or predominantly endogenous technology transfer. General risk factors are presented and analyzed from a CDM project's life cycle's perspective. The results show that Brazilian energy CDM projects contribute to cleaner technology generation and to the promotion of triple bottom line (social, economic, and environmental) sustainable development.     

The proteomes of feedstocks used for the production of second‐generation ethanol: a lacuna in the biofuel era

Maize, sorghum, sugarcane, switchgrass and miscanthus are the main crops suggested as potential sources of lignocellulosic biomass for the production of second‐generation ethanol. The attention these crops have received has been concentrated in the field of genomics, and very little research has been performed in the field of proteomics, particularly in the cell wall proteomic, despite the importance of these crops in biofuel production. New mass spectrometry‐based proteomic methods allow the identification and quantification of thousands of proteins in complex mixtures, as well as the detection of post‐translational changes in complex proteomes, providing important insight into the downstream consequences of gene expression. Together with other ‘omic’ approaches, proteomic might be decisive to bring new information in the study of cell wall formation. Here, we briefly highlight proteomic techniques and review the research that has been completed on the proteomes of these five crops.     

Global environmental change effects on ecosystems: the importance of land‐use legacies

One of the major challenges in ecology is to predict how multiple global environmental changes will affect future ecosystem patterns (e.g. plant community composition) and processes (e.g. nutrient cycling). Here, we highlight arguments for the necessary inclusion of land‐use legacies in this endeavour. Alterations in resources and conditions engendered by previous land use, together with influences on plant community processes such as dispersal, selection, drift and speciation, have steered communities and ecosystem functions onto trajectories of change. These trajectories may be modulated by contemporary environmental changes such as climate warming and nitrogen deposition. We performed a literature review which suggests that these potential interactions have rarely been investigated. This crucial oversight is potentially due to an assumption that knowledge of the contemporary state allows accurate projection into the future. Lessons from other complex dynamic systems, and the recent recognition of the importance of previous conditions in explaining contemporary and future ecosystem properties, demand the testing of this assumption. Vegetation resurvey databases across gradients of land use and environmental change, complemented by rigorous experiments, offer a means to test for interactions between land‐use legacies and multiple environmental changes. Implementing these tests in the context of a trait‐based framework will allow biologists to synthesize compositional and functional ecosystem responses. This will further our understanding of the importance of land‐use legacies in determining future ecosystem properties, and soundly inform conservation and restoration management actions.     

Influence of the flocculating agent in sedimentation and performance of a non flocculent strain of Zymomonas mobilis in the ethanol production process

The influence of the flocculating agent was studied in the performance (measured by microbial growth and ethanol production) of a non flocculent strain of Zymomonas mobilis, as well as the potentiality of the sedimentation process in the separation of the biomass from the fermentation broth. Among the flocculating agents studied, it was verified that both tannin and the polyelectrolyte yielded good results with regard to cellular performance. However, with regard to sedimentation tannin is more adequate to be used in processes involving Zymomonas mobilis.     

Life-cycle variation in the aphid Sitobion avenae: costs and benefits of male production

Abstract 1. Patterns of male production and life-cycle variation were investigated in the aphid Sitobion avenae . Seventy-seven field-collected clones were subjected to a 14 °C short day-length regime to assess their reproductive modes, and three clones were used to study life-cycle inheritance. A further analysis assessed the cost of male production.
2. In comparison with those from East Anglia, there were more holocyclic and intermediate clones found in Scottish populations, and they produced significantly more mating females. In total, 44% of clones were androcyclic.
3. The inheritance of life cycle showed a greater level of complexity than could be achieved by previously suggested monohybrid inheritance mechanisms.
4. Holocyclic and intermediate clones produced a higher proportion of males than did androcyclic clones. Inter-clonal differences were reflected in the pattern of male production in the reproductive sequence.
5. A significant cost was associated with male production in terms of a reduction in both fecundity and total offspring biomass.
6. Winged females rarely gave birth to males but the pattern of mating female production differed between holocyclic and intermediate clones.
7. Patterns of male and mating female production by the different types of clone may be related to different advantages and disadvantages of dispersal and inbreeding.
8. Recent models of aphid overwintering could be enhanced by consideration of issues raised in this study, such as the cost of male production, the inheritance of life cycle, and the patterns of sexual morph production.     

Eco‐evolutionary partitioning metrics: assessing the importance of ecological and evolutionary contributions to population and community change

Interest in eco‐evolutionary dynamics is rapidly increasing thanks to ground‐breaking research indicating that evolution can occur rapidly and can alter the outcome of ecological processes. A key challenge in this sub‐discipline is establishing how important the contribution of evolutionary and ecological processes and their interactions are to observed shifts in population and community characteristics. Although a variety of metrics to separate and quantify the effects of evolutionary and ecological contributions to observed trait changes have been used, they often allocate fractions of observed changes to ecology and evolution in different ways. We used a mathematical and numerical comparison of two commonly used frameworks – the Price equation and reaction norms – to reveal that the Price equation cannot partition genetic from non‐genetic trait change within lineages, whereas the reaction norm approach cannot partition among‐ from within‐lineage trait change. We developed a new metric that combines the strengths of both Price‐based and reaction norm metrics, extended all metrics to analyse community change and also incorporated extinction and colonisation of species in these metrics. Depending on whether our new metric is applied to populations or communities, it can correctly separate intraspecific, interspecific, evolutionary, non‐evolutionary and interacting eco‐evolutionary contributions to trait change.     

Bed-building in captive chimpanzees (Pan troglodytes): the importance of early rearing

In the wild, great apes sleep in beds they make by successively bending branches into an interwoven platform. These beds are functionally more closely related to human beds than they are to the nests and tree-holes used by other primate species. The idea that bed-building by great apes is learned behavior that is dependent on appropriate early experiences has been proposed but never fully tested. In the present study this hypothesis was indirectly tested in 73 captive adult chimpanzees (Pan troglodytes; 27 wild-born and 46 captive-born). Bed-building and use were tested experimentally by the introduction of three sets of bedding materials. Over 200 hr of scan-sampling data were collected during 45-min observations following introduction of the bedding material. The wild-born subjects built and used beds significantly more often than the captive-born subjects. Also, wild-born subjects used more complex techniques during construction. Captive-born subjects that were mother-reared through early adolescence spent more time building and using beds than their nursery-reared counterparts. These differences remained consistent even when previous adult experience with bedding (measured as naturalistic vs. traditional housing) was accounted for. These results suggest that bed-building is a learned behavior that requires early experience and practice for acquisition.     

Immigrants and refugees: the importance of dispersal in mediating biotic attrition under climate change

Montane tropical rainforests are critically important areas for global bird diversity, but are projected to be highly vulnerable to contemporary climate change. Upslope shifts of lowland species may partially offset declines in upland species but also result in a process of lowland biotic attrition. This latter process is contingent on the absence of species adapted to novel warm climates, and isolation from pools of potential colonizers. In the Australian Wet Tropics, species distribution modelling has forecast critical declines in suitable environmental area for upland endemic birds, raising the question of the future role of both natural and assisted dispersal in species survival, but information is lacking for important neighbouring rainforest regions. Here we use expanded geographic coverage of data to model the realized distributions of 120 bird species found in north‐eastern Australian rainforest, including species from potential source locations in the north and recipient locations in the south. We reaffirm previous conclusions as to the high vulnerability of this fauna to global warming, and extend the list of species whose suitable environmental area is projected to decrease. However, we find that expansion of suitable area for some species currently restricted to northern rainforests has the potential to offset biotic attrition in lowland forest of the Australian Wet Tropics. By examining contrasting dispersal scenarios, we show that responses to climate change in this region may critically depend on dispersal limitation, as climate change shifts the suitable environmental envelopes of many species south into currently unsuitable habitats. For lowland and northern species, future change in vegetation connectivity across contemporary habitat barriers is likely to be an important mediator of climate change impacts. In contrast, upland species are projected to become increasingly isolated and restricted. Their survival is likely to be more dependent on the viability of assisted migration, and the emergence and persistence of suitable environments at recipient locations.     

Defining the importance of including transient ecosystem responses to simulate C‐cycle dynamics in a global change model

The ability of plant species to migrate is one of the critical issues in assessing accurately the future response of the terrestrial biosphere to climate change. This ability is confined by both natural and human‐induced changes in land cover. In this paper we present land‐cover and Carbon (C) cycle models designed to simulate the biospheric consequences of different types of land‐cover changes. These models, imbedded in the larger integrated assessment model IMAGE 2, were used to demonstrate the importance of considering spatial aspects for global C‐cycle modelling. A gradual‐migration, an unlimited‐migration and a no‐migration case were compared to show the range of possible consequences. Major differences between these cases were simulated for land‐cover patterns and the carbon budget. A large geographical variation in the biospheric response was also simulated. The strongest response was simulated in high‐latitude regions, especially for the migration cases in which land‐cover changes were permitted. In low‐latitudes regions the differences between the migration cases were smaller, mainly due to the effects of land‐use changes. The geographical variation among, and the different responses, the migration cases clearly demonstrate how essential it is to assess biospheric responses to climate change and land use simultaneously. Moreover, it also shows the urgent need for enhanced understanding of spatial and temporal dynamics of the biospheric responses.     

Fitness costs and morphological change of laboratory‐selected thiamethoxam resistance in the B‐type Bemisia tabaci (Hemiptera: Aleyrodidae)

Thiamethoxam has been used as a key insecticide to control the whitefly, B‐type Bemisia tabaci, for several years in China with no known cases of resistance in field populations. To evaluate the risk of resistance, a field population was collected and resistant strains were developed by exposure to thiamethoxam in the laboratory. After selection for 36 generation, a strain with 60‐fold resistance was successfully identified. Fitness analysis by constructing life tables, demonstrated that resistant B‐type whiteflies had obvious fitness disadvantages in their development and reproduction. The fitness of resistant B‐type whiteflies decreased dramatically, to only one‐half that of the susceptible strain. Some changes in the morphological characteristics of the resistant strain were observed. The lengths of first, second and third instars of the resistant strain were significantly smaller than those of the susceptible strain, and the width of the first and the fourth instars were also significantly smaller than in the susceptible strain. Our results suggest that the B‐type B. tabaci has the potential to develop high resistance to thiamethoxam, and that the resistance changed the morphology of the insects. The slow development of resistance and the lower fitness of resistant B. tabaci strains may result in a quick recovery of sensitivity when the population is no longer in contact with thiamethoxam in the field.     

Climatic drivers of leaf traits and genetic divergence in the tree Annona crassiflora: a broad spatial survey in the Brazilian savannas

The Cerrado is the largest South American savanna and encompasses substantial species diversity and environmental variation. Nevertheless, little is known regarding the influence of the environment on population divergence of Cerrado species. Here, we searched for climatic drivers of genetic (nuclear microsatellites) and leaf trait divergence in Annona crassiflora, a widespread tree in the Cerrado. The sampling encompassed all phytogeographic provinces of the continuous area of the Cerrado and included 397 individuals belonging to 21 populations. Populations showed substantial genetic and leaf trait divergence across the species' range. Our data revealed three spatially defined genetic groups (eastern, western and southern) and two morphologically distinct groups (eastern and western only). The east‐west split in both the morphological and genetic data closely mirrors previously described phylogeographic patterns of Cerrado species. Generalized linear mixed effects models and multiple regression analyses revealed several climatic factors associated with both genetic and leaf trait divergence among populations of A. crassiflora. Isolation by environment (IBE) was mainly due to temperature seasonality and precipitation of the warmest quarter. Populations that experienced lower precipitation summers and hotter winters had heavier leaves and lower specific leaf area. The southwestern area of the Cerrado had the highest genetic diversity of A. crassiflora, suggesting that this region may have been climatically stable. Overall, we demonstrate that a combination of current climate and past climatic changes have shaped the population divergence and spatial structure of A. crassiflora. However, the genetic structure of A. crassiflora reflects the biogeographic history of the species more strongly than leaf traits, which are more related to current climate.     

The spatial distribution of forest biomass in the Brazilian Amazon: a comparison of estimates

The amount of carbon released to the atmosphere as a result of deforestation is determined, in part, by the amount of carbon held in the biomass of the forests converted to other uses. Uncertainty in forest biomass is responsible for much of the uncertainty in current estimates of the flux of carbon from land‐use change. In the present contribution several estimates of forest biomass are compared for the Brazilian Amazon, based on spatial interpolations of direct measurements, relationships to climatic variables, and remote sensing data. Three questions were posed: First, do the methods yield similar estimates? Second, do they yield similar spatial patterns of distribution of biomass? And, third, what factors need most attention if we are to predict more accurately the distribution of forest biomass over large areas? The answer to the first two questions is that estimates of biomass for Brazil's Amazonian forests (including dead and belowground biomass) vary by more than a factor of two, from a low of 39 PgC to a high of 93 PgC. Furthermore, the estimates disagree as to the regions of high and low biomass. The lack of agreement among estimates confirms the need for reliable determination of aboveground biomass over large areas. Potential methods include direct measurement of biomass through forest inventories with improved allometric regression equations, dynamic modelling of forest recovery following observed stand‐replacing disturbances, and estimation of aboveground biomass from airborne or satellite‐based instruments sensitive to the vertical structure plant canopies.