Abstract The development of new technologies which increase the production of biofuel without directly compete with food production is required. Microalgal biomass has recently been in the highlight. The role of this biomass is here discussed within the concept of biorefinery and industrial sustainability of bioethanol production. The process of cultivation in order to accumulate around 50% of carbohydrates in the biomass (dry weight) and the importance of water and nutrient recycling are reviewed. Saccharification of biomass using enzymes or acids and alternative processes such as hydrothermal liquefaction and flash hydrolysis are addressed. Since the main monosaccharide in microalgal biomass is glucose, high rates of hydrolysis and fermentation were, generally, achieved (more than 80% of the efficiency as a sum of these two processes). Anaerobic digestion to treat vinasse and the recycling of CO2 from the ethanolic fermentation and biogas could increase the process sustainability. Alternative techniques for the concentration of bioethanol from fermentation broth and for the optimization of fuel transportation are mentioned. Finally, the advantage of using microalgae rather than other sources is estimated with reference to the production rate, even though the cultivation costs are still high.

ABSTRACT Fruit pulp is the most basic food product obtained from fresh fruit processing. Fruit pulps can be cold stored for long periods of time, but they also can be used to fabricate juices, ice creams, sweets, jellies and yogurts. The exploitation of tropical fruits has leveraged the entire Brazilian fruit pulp sector due mainly to the high acceptance of their organoleptic properties and remarkable nutritional facts. However, several works published in the last decades have pointed out unfavorable conditions regarding the consumption of tropical fruit pulps. This negative scenario has been associated with unsatisfactory physico-chemical and microbiological parameters of fruits pulps as outcomes of little knowledge and improper management within the fruit pulp industry. There are protocols for delineating specific identity and quality standards (IQSs) and standardized good manufacturing practices (GMP) for fruit pulps, which also embrace standard operating procedures (SOPs) and hazard analysis and critical control points (HACCP), although this latter is not considered mandatory by the Brazilian legislation. Unfortunately, the lack of skilled labor, along with failures in complying established protocols have impaired quality of fruit pulps. It has been necessary to collect all information available with the aim to identify the most important hazards within fruit pulp processing lines. Standardizing methods and practices within the Brazilian fruit pulp industry would assurance high quality status to tropical fruit pulps and the commercial growth of this vegetal product towards international markets.

A vinhaça de cana-de-açúcar é um dos resíduos mais poluidores da indústria sucroalcooleira brasileira, principalmente pelas suas características nocivas ao meio ambiente, como o elevado teor de matéria orgânica e acidez. A digestão anaeróbia é um método altamente eficiente de tratamento de efluente e pode ser usada para tratar este resíduo. O estudo aborda a biodigestão anaeróbia de vinhaça de cana-de-açúcar em condições mesófilas (30 - 45°C), variando a concentração de inóculo (0,5 a 5,5%) e o pH (6 - 8). Foram verificados a remoção de DQO (Demanda Química de Oxigênio) e o teor de sólidos totais, além do rendimento e composição do biogás após a biodigestão da vinhaça. A vinhaça foi eficientemente digerida sob condições mesófilas em 23 dias de TRH (Tempo de Retenção Hidráulico) e 5 dias de fase acidogênica, com consequente redução de DQO (54 - 83%) e de sólidos totais de (52 - 87%). As análises estatísticas sugeriram que a temperatura, a concentração de inóculo e o pH não foram suficientes para caracterizar o processo de biodigestão anaeróbia da vinhaça, não apresentando diferença significativa entre os ensaios. Os parâmetros ótimos de operação foram definidos como temperatura entre 30 e 35°C, concentraçao de inóculo de 0,5% e pH entre 6 e 7. Os resultados evidenciam o uso promissor da vinhaça tratada como biofertilizante para a agricultura, indicando a digestão anaeróbia como um processo sustentável e ótima opção para as empresas sucroalcooleiras brasileiras.

Sugarcane vinasse is one of the most polluting residues produced by Brazilian ethanol industries, mainly because of its harmful effects on the environmental, such as high organic matter load and acidity. Anaerobic digestion is a highly efficient wastewater treatment method that could potentially be used to treat sugarcane vinasse. This study examined the anaerobic biodigestion of sugarcane vinasse in mesophilic conditions (30 - 45°C) by varying the inoculum concentration (0.5 to 5.5%) and pH (6 - 8). Changes of Chemical Oxygen Demand (COD), total solids content, and yield and composition of biogas after the biodigestion of the vinasse were assessed. The vinasse was efficiently digested under mesophilic anaerobic conditions over a 23-day Hydraulic Retention Time (HRT) and a 5-day acidogenic phase with a consequent reduction of COD (54 - 83%) and total solids (52 - 87%). Statistical analyses at a confidence level of 95% suggested that temperature, pH and inoculum concentration did not influence on the anaerobic biodigestion of the vinasse. The optimal operating parameters were found to be temperatures of 30 - 35°C, inoculum concentration of 0.5% and pH of 6 - 7. The results emphasize the promising use of the treated sugarcane vinasse as a biofertilizer for agriculture, indicating that the anaerobic digestion process is an excellent alternative for Brazilian ethanol industries.

RESUMO: O crescimento populacional e a busca por alimentos saudáveis levam a um aumento do consumo da água de coco e, com isso, um impacto ambiental pela maior geração de resíduos, merecendo atenção de pesquisadores para o aproveitamento dessa biomassa, em que uma das tecnologias empregadas é a produção de combustíveis renováveis. Este trabalho avalia a fibra da casca de coco verde pré-tratada com álcali, hidrolisada com enzima e submetida à fermentação etanólica com a levedura comercial Saccharomyces cerevisiae. Apesar da significativa perda em celulose (4,42% em relação à biomassa e 17,9% em relação à celulose presente), o pré-tratamento alcalino apresentou alta solubilização de lignina (80%), tornando-se viável para estudos da produção de etanol 2G. A hidrólise enzimática converteu 87% dos açúcares e a fermentação etanólica consumiu 81% do substrato presente no hidrolisado, gerando uma eficiência na conversão de açúcares em etanol de 59,6%. Tais resultados indicam a casca de coco verde como uma alternativa promissora à produção de energia renovável.

ABSTRACT: Population growth and the increasing search for healthy foods have led to a major consumption of coconut water and, hence, to an environmental impact caused by the inappropriate disposal of green coconut husks. This lignocellulosic biomass has deserved attention of researchers concerning the seeking of new usages, as, for example, in renewable fuels production technologies. This study examines the potential of green coconut husk fibers as a feedstock for the production of bioethanol. The coconut fibers were pretreated through an alkaline method, hydrolyzed enzymatically and submitted to ethanol fermentation with commercial yeasts of Saccharomyces cerevisiae. Despite the significant loss of cellulose (4.42% in relation to the fiber and 17.9% concerning the original cellulose content), the alkaline pretreatment promoted an efficient solubilization of lignin (80%), turning the coconut fibers into a feasible raw material for 2G ethanol production studies. Enzymatic hydrolysis converted 87% of the sugars and the ethanolic fermentation consumed 81% of the substrate in the hydrolyzate, leading to a sugar to ethanol convertion efficiency of 59.6%. These results points out that green coconut husks are a promising alternative to the production of renewable energy.