• Energy Research

Currently, the continuous depletion of non-renewable resources of fuels and chemicals has promoted the research and development of different alternatives for the replacement of fossil resources as the feedstock of fuels and chemicals. At present, one of the most important biofuels in the current economy, is bioethanol, contributing to 65% of the total biofuels production. The production of bioethanol is an attractive alternative because it would be produced using indigenous and native raw material, therefore, the socioeconomic impact mainly in developing countries would be measured by the economic incomes and increase the quality of life of small and middle farmers. The first-generation ethanol production from sugarcane, corn, or beet sugar is broadly implemented at an industrial scale. However, the second-generation ethanol (2GE) is currently still in development stages, looking for different alternatives according to each region under study. The 2GE is also subject of diverse opinions about its economic viability and its real impact on the environment, especially due to the CO2 footprint. Consequently, this chapter has presented an overview of 2GE production, the possibilities of co-production of molecules of high value-added, and their economic and environmental assessment, including CO2 release, water consumption, solid residues disposal, and economic analysis to determine the best bioethanol based biorefinery configuration.

Microalgae are sources of nutritional products and biofuels. However, their economical processing is challenging, because of (i) the inherently low concentration of biomass in algal cultures, below 0.5%, (ii) the high-water content in the harvested biomass, above 70%; and (iii) the variable intracellular content and composition. Cell wall structure and strength vary enormously among microalgae, from naked Dunaliella cells to robust Haematococcus cysts. High-value products justify using fast and energy-intensive processes, ranging from 0.23 kWh/kg dry biomass in high-pressure homogenization, to 6 kWh/kg dry biomass in sonication. However, in biofuels production, the energy input must be minimized, requiring slower, thermal or chemical pretreatments. Whichever the primary fraction of interest, the spent biomass can be processed into valuable by-products. This review discusses microalgal cell structure and composition, how it affects pretreatment, focusing on technologies tested for large scale or promising for industrial processes, and how these can be integrated into algal biorefineries.

Microalgae are versatile sources of bioproducts, a solution for many environmental problems. However, and despite its importance, one of the main problems in large-scale cultures-the presence of contaminants-is rarely systematically approached. Contamination, or the presence of undesirable organisms in a culture, is deleterious for the culture and frequently leads to culture crashes. To avoid contamination, closed systems can be used; however, for very large-scale open systems, contamination is unavoidable and remediation procedures are necessary-ranging from physicochemical treatment to addition of biocidal substances. In all cases, early detection and culture monitoring are paramount. This article describes the biological contaminants, contamination mechanisms, and control systems used in open and closed cultures, discussing the latest advances and techniques in the area. It also discusses the complex interactions of algae with other microorganisms that can be expected in cultivation systems.

AbstractSouth America is responsible for 16% of the world's agricultural production and 21% of the world's livestock. Palm harvesting has been gaining special attention, with constant growth in Brazil, Colombia, and Ecuador. Fast expansion in palm plantations in the equatorial zone around the world has been motivated by an increase in farming of species such as Elaeis guineensis, Elaeis oleifera , and Elaeis odora. Parallel to the increase of oil‐palm harvesting, the generation of residues is an important aspect to take into consideration. This work presents an overview of palm cultivation in South America, focusing on the full use of the fruits of the palm for biodiesel production. It also discusses the status of the main projects in South America for second‐generation biofuels production from governmental agencies and private institutes. From the data consulted it was determined that Colombia, Ecuador, and Brazil have policies and incentives for the agrobusiness of oil‐palm production. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd

AbstractPopulation growth has generated an enormous increase in demand for energy and chemicals to supply goods and services and to maintain quality of life. Oil, coal, and natural gas are the primary sources of the chemicals and energy that directly impact the economy. However, the reserves of these resources are continuously reducing. New alternatives have emerged, including biotechnological tools such as microbial consortia (MC) to produce biofuels, chemicals such as organic acids, and processed foods. The diversity of MC as a biotechnological tool allows it to be used in complex substrates, opening the possibility of using other solid waste to implement consolidated bioprocesses (CPs). This review presents an overview of the uses of MC and CP for producing biofuels using different feedstocks.

The sugarcane industry is one of the largest in the world and processes huge volumes of biomass, especially for ethanol and sugar production. These processes also generate several environmentally harmful solid, liquid, and gaseous wastes. Part of these wastes is reused, but with low-added value technologies, while a large unused fraction continues to impact the environment. In this review, the classic waste reuse routes are outlined, and promising green and circular technologies that can positively impact this sector are discussed. To remain competitive and reduce its environmental impact, the sugarcane industry must embrace technologies for bagasse fractionation and pyrolysis, microalgae cultivation for both CO2 recovery and vinasse treatment, CO2 chemical fixation, energy generation through the anaerobic digestion of vinasse, and genetically improved fermentation yeast strains. Considering the technological maturity, the anaerobic digestion of vinasse emerges as an important solution in the short term. However, the greatest environmental opportunity is to use the pure CO2 from fermentation. The other opportunities still require continued research to reach technological maturity. Intensifying the processes, the exploration of driving-change technologies, and the integration of wastes through biorefinery processes can lead to a more sustainable sugarcane processing industry.

The ability to produce second-generation itaconic acid by Aspergillus terreus, and the inhibitory effects of hydrolysis by-products on the fermentation were evaluated by cultivation in a synthetic medium containing components usually present in a real hydrolysate broth from lignocellulosic biomasses. The results showed that A. terreus NRRL 1960 can produce itaconic acid and consume xylose completely, but the conversion is less than the fermentation using only glucose. In addition, compared to fermentation of glucose, or even xylose, the mix of both sugars resulted in a lower itaconic acid yield. In the inhibitory test, the final itaconic acid titer was reduced by acetic acid, furfural, and 5-hydroxymethylfurfural concentrations of, respectively, 188, 175, and 700 mg L-1. However, the presence of any amount of acetic acid proved to be detrimental to itaconic acid production. This research sheds some light on doubts about the biorefinery implementation of itaconic acid production.