Plant-Based Genetic Tools for Biofuels Production

The application of biotechnology has had great impact on the agricultural sciences. Micropropagation, in particular, is one of the biotechnological methods whose major achievements have contributed to the development of agriculture in Northeast Argentina, and it is used in the mass production of aromatic, medicinal, fruit, ornamental, and forest plant species. It is normally applied to certified cultivars with good productive performance, providing significant development to the sector. Micropropagation also provides significant production and economic benefits, and an unprecedented environmental contribution.

Biofuel production represents an important alternative for replacing fossil fuels and reducing the emission of greenhouse gases into the atmosphere. With increasing demands for renewable fuel to replace fossil fuels, research on new energy sources is becoming more popular and new approaches in research techniques are occurring. In this context, the uses of somatic and gametic embryogenesis, cell suspension, and protoplast fusion in biofuels production will be presented in this chapter. Gametic embryogenesis is a convenient alternative in plant breeding because it makes possible the development of homozygous lines, increasing efficiency and speed in conventional breeding programs. Somatic embryogenesis is an important tool for plant cloning, looking toward the obtaining of improved plants by cell suspension culture or protoplast fusion. Suspension of plant cell cultures has several uses and applications for improving agronomical traits, and it is widely used in biotechnology for micropropagation, for the production of secondary metabolites or other substances, for obtaining somatic hybrids through protoplast fusion, and for modifying plants through genetic transformation. Protoplast fusion has been used by plant breeders to overcome the genetic barriers of outcrossing in incompatible plants, producing hybrid plants with different degrees of ploidy for improved agronomic and horticultural traits. In this chapter, current research with species that have potential to improve biofuel production is presented, with the aim of giving insights on the ways that these techniques can be used to produce renewable fuels.

All living organisms are constantly exposed to DNA-damaging agents, leading to the accumulation of chemical and structural modifications which can affect key processes such as replication and transcription. Various DNA repair pathways have evolved for dealing with these modifications, thus preventing their toxic and mutational potential. Mutations in mtDNA are frequently observed in several diseases, which are reflected in metabolic changes or even in the attenuation of apoptotic response to anticancer therapies. To the integrity of the mitochondrial genome, repair mechanisms are recruited to the organelle. Among these, the BER pathway is the main pathway localized to mitochondria. The identification of mechanisms that prevent the accumulation of DNA damage in plants with agricultural interest can lead to improvements of these crops, including sugarcane, thus leading to improvements in sugarcane processing and consequently in the production of biofuels.

A growing world population is demanding food and energy at the highest pace in the history of human kind. Plant biotechnology oriented to sustainable and competitive agriculture should lead a trail of innovation in order to address these emerging needs. The last decade has been characterized by the explosive accumulation of vast amounts of discoveries in the field of molecular biology. These achievements have paved the way for the advent of novel developments in plant biotechnology. Several new tools are being applied for genetic crop improvement every day, based on breakthrough versatile platforms that are increasing effectiveness and speed in the generation of new varieties of crops. The latest achievements are not only adaptations or improvements of modern techniques such as intra- and cis-genesis and accelerated breeding based on transgenics and null-segregants, meganucleases, and zinc finger nucleases; they are also the dawn of new disruptive technologies that are reshaping the paradigm of genetic improvement, as is the case with TALEN and CRISPR/Cas. Sitedirected genome editing is becoming precise, cost-effective, versatile, and fast. These new breeding platforms are leading the way to next generation biotechnology. This chapter discusses the most recent updates and developments of new breeding techniques, paradigmatic achievements, future perspectives, and challenges in the context of plant biotechnology.

The current interest in green technologies has directed attention to the use of plant systems for several applications, including traditional crop plant systems used for biomass production, large-scale synthesis of a great number of recombinant proteins, and biofuels production. In this context, plant viruses are very useful instruments for plant biotechnology applications, constituting suitable tools for heterologous gene expression. Virions are particles with a complex composition, but their stability allows them to be used for the development of numerous biotechnological applications and as research tools for plant functional genomics studies. The development of infectious full-length viral clones is a strategy extensively employed as an alternative tool for introducing viruses into plants via inoculation with Agrobacterium tumefaciens. Another strategy, called RNA interference, a plant gene expression regulation mechanism based on post-transcriptional gene silencing, has extensively been employed to down-regulate the expression of endogenous transcripts and displays a number of biotechnological applications. Additionally, transgenic expression of viral proteins has been used to achieve pathogen-derived resistance, a mechanism that confers resistance to viral infections in agricultural crops. In this chapter we will discuss several strategies and methods for plant gene expression which employ plant viruses developed over the past decade.

This chapter reviews the importance and application of proteomics tools for studying bioenergy crops and microorganisms employed in sugar fermentation and/or degradation of cell wall compounds. The large volume of information from genome sequencing projects has allowed the development of many new platforms for profiling each step of the genetic information flow from DNA to protein to many molecular interactions involved in phenotype determination. In this context, proteomics is a comprehensive package of tools dedicated to identifying and characterizing protein expression in different biological systems. In this article, the application of proteomics in bioenergy production from feedstock is summarized, citing studies associated with the reduction of lignocellulose biomass recalcitrance and the discovery of more efficient enzymes for cell wall disruption and of potent microorganisms for sugar fermentation.

The quest for a renewable and inexpensive source of energy is one of the greatest challenges of the 21st century. Plants have already been used as a renewable source of energy, and continue to be one of the greatest hopes in this area. In order for plants to continue providing a cost-effective and renewable source of energy, it is imperative that their biomass growth and quality be constantly improved. Recent advances in the genomics field, led by the development of high-throughput sequencing and genotyping platforms, have opened up new strategies for accelerating plant breeding and aiding biotechnology development. Analyses of the vast amount of data generated by these modern genomics platforms are only possible with the constant development of computers and bioinformatics tools. In this chapter, we will present the genomic resources available for the most important plant species with bioenergy potential. Bioinformatics tools for gene expression analyses with RNA-Seq and for SNP genotyping are also presented.

Plant biomass is the feedstock for biofuel production. Efforts to maximize yield per unit of production area are of crucial importance in meeting the rising demand for renewable energy sources. Plantation, irrigation, use of fertilizers and pesticides, together with harvest, represent the major costs involved in biomass production. In this chapter we give a broad overview of (i) the factors influencing biomass yield (such as water and nutrients) and advances in cultivation technologies, discussing sustainability issues and the link of these practices with industry needs, and (ii) the relation of these conditions to the physiology of energy crops, presenting innovative technologies that can support management decisions. We will focus on sugarcane as a model for bioenergy crops.

The production of biofuels by fermentation is as old as mankind itself. The use of yeast (Saccharomyces cerevisiae) in the production of wine and beer, as well as bread, has been known from the time of the Rosetta Stone and the Bible. Nowadays, biotechnology is playing a major role in new advances in the fermentation of different substrates and in the production of ethanol, as well as in the production of biodiesel and many other biofuels. Advances in biotechnology have shed new light on ancient and well established technologies, bringing biofuels and mankind to a new, clean, sustainable, and bright future. A single and simple biotechnology method (electrophoretic karyotyping of intact chromosomes) has brought the entire ethanol industry in Brazil to new horizons.

At present, fuels derived from biomass play an important role in scenarios for the expansion of renewable energy worldwide. Considering the liquid biofuels, biodiesel is an interesting alternative that minimizes mineral diesel consumption. Among the raw materials available for biodiesel production, microalgae biomass has been described as an alternative with great potential for accomplishing the goal of replacing diesel by biodiesel without competing with fertile land for food production. This paper presents advances and challenges in the technologies presently used for the production of biodiesel from microalgae, including the procedures used to obtain biomass and the evolving technologies for reducing production steps (and consequently time and process costs). It was found that microalgae is currently still not a viable option for large-scale biodiesel production, as it has a negative energy balance. On the other hand, microalgae indicates substantial earning potential in biomass and lipid fractions, being a good alternative because of its high fat content. Therefore, research directed toward the production of biofuels from microalgae should receive greater attention and investment. Microalgae can become a competitive alternative and a commercial reality in the biofuels sector with the development of genetic improvement and technological production systems and with hoped-for reductions in costs, and also because of its sustainable qualities in contrast to other raw materials.