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Mixotrophic cultivation of microalgae provides a very promising alternative for producing carbohydrate-rich biomass to convert into bioethanol and value-added biocompounds, such as vitamins, pigments, proteins, lipids and antioxidant compounds. Spirulina platensis may present high yields of biomass and carbohydrates when it is grown under mixotrophic conditions using cheese whey. However, there are no previous studies evaluating the influence of this culture system on the profile of fatty acids or antioxidant compounds of this species, which are extremely important for food and pharmaceutical applications and would add value to the cultivation process. S. platensis presented higher specific growth rates, biomass productivity and carbohydrate content under mixotrophic conditions; however, the antioxidant capacity and the protein and lipid content were lower than that of the autotrophic culture. The maximum biomass yield was 2.98 ±0.07 g/L in growth medium with 5.0% whey. The phenolic compound concentration was the same for the biomass obtained under autotrophic and mixotrophic conditions with 2.5% and 5.0% whey. The phenolic compound concentrations showed no significant differences except for that in the growth medium with 10.0% whey, which presented an average value of 22.37±0.14 mg gallic acid/g. Mixotrophic cultivation of S. platensis using whey can be considered a viable alternative to reduce the costs of producing S. platensis biomass and carbohydrates, shorten cultivation time and produce carbohydrates, as it does not require adding expensive chemical nutrients to the growth medium and also takes advantage of cheese whey, an adverse dairy industry byproduct.

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Biomass feedstocks such as algae and cyanobacteria are highly sought after because of their high reproduction rates and growth densities, but their high concentrations of O and N heteroatoms are problematic for biofuel applications. Mild upgrading processes are necessary for producing fungible fuels from these renewable sources. We developed a process to upgrade spirulina-based bio-oil from tail-gas reactive pyrolysis (TGRP), using a combination of catalytic hydrotreatment and purification of the upgraded product. The TGRP bio-oil was distillated at high organic yields, and the distillates served as the feedstock for catalytic upgrading. Simultaneous hydrodeoxygenation and hydrodenitrogenation (HDO/HDN) was carried out in one step using a commercial ruthenium catalyst on carbon support. Using bio-oil distillates as feedstocks for hydrotreatment produced hydrocarbons at high space velocities. Reactor temperature was the critical variable, wherein the optimal temperature compromised between excessive yields loss and catalyst inactivity. While the HDO/HDN product contained relatively significant amounts of residual O and N (∼1 wt % each), the remaining O and N-containing compounds were removed via single aqueousphase extraction with hydrochloric acid. The extraction step serves as a milder alternative to deep HDO/HDN processes that diminish final product yields.

This literature review discusses the concepts and factors that influence industrial cheese yield and compiles the latest studies conducted in Brazil involving this theme. In seeking to support managerial decision-making, cheese yield can be measured at the end of processing or estimated prior to this. In research and industry, measuring and estimating yield can be evaluated under the effect of processing, from different proportions and characteristics of ingredients (mainly milk quality), to processing factors involving the steps of the actual production (handling of the raw material and the curd coagulation conditions, salting, maturation, etc.) and the equipment. The number of Brazilian studies that have sought to answer questions about this topic in recent years was reasonable. The vast majority of them considered yield in its most basic aspect, which is obtained by measuring what was produced. Few studies used the perspective of prediction, indicating that there is room for a more empirical approach that allows for obtaining other types of answers regarding efficiency in the production of cheese, and which is shown as an opportunity for Brazilian research to advance.Keywords: efficiency; equation; cheese production.Practical Application: Understanding how cheese yield is evaluated and how Brazilian research has treated it.Cheese yield in Brazil: state of the art Food Sci. Technol, Campinas, 36(4): 563-569, Oct.-Dec. 2016 564 the key search words used were: "rendimento", "queijo", "yield", "cheese" and "cheese yield".

Biofuels have been seen as potential sources to meet future energy demand as a renewable and sustainable energy source. Despite the fact that the production technology of first-generation biofuels is consolidated, these biofuels are produced from foods crops such as grains, sugar cane, and vegetable oils competing with food for crop use and agricultural land. In recent years, it was found that microalgae have the potential to provide a viable alternative to fossil fuels as source of biofuels without compromising food supplies or arable land. On this scenario, this paper aims to demonstrate the energetic potential to produce bio-oil and chemicals from microalgae Chlorella vulgaris and Arthrospira platensis. The potential of these biomasses was evaluated in terms of physical-chemical characterization, thermogravimetric analysis, and analytical pyrolysis interfaced with gas chromatograph (Py-GC/MS). The results show that C. vulgaris and A. platensis are biomasses with a high heating value (24.60 and 22.43 MJ/kg) and low ash content, showing a high percentage of volatile matter (72.49 and 79.42%). These characteristics confirm their energetic potential for conversion process through pyrolysis, whereby some important aromatic compounds such as toluene, styrene, and phenol were identified as pyrolysis products, which could turn these microalgae a potential for biofuels and bioproduct production through the pyrolysis.

Microalgae has a great potential to produce biofuels and bioproduct but the cost is still too high mainly due to the biomass production. Mixotrophic cultivation has been pointed as microalgae cultivation mode for biomass/bioenergy production with lower cost and able to make remediation of organic waste. The proposals of this work was to make a review of microalgae growth under mixotrophic condition using agro-industrial waste. Agro-industrial by-products and wastes are of great interest as cultivation medium for microorganisms because of their low cost, renewable nature, and abundance. However biotechnological technologies are necessary to develop the production of microalgae on a large scale.

Pyrolysis of spirulina, a cyanobacteria with high levels of protein (74 wt %) and low levels of lipid (0.8 wt %) content, has the potential to produce fuels and platform chemicals that differ from those produced from lignocellulosic materials. The yields and product distribution from fluidized-bed pyrolysis of spirulina using the U.S. Department of Agriculture - Agricultural Research Service’s tail gas reactive pyrolysis (TGRP) process were evaluated and compared with those produced under an inert atmosphere. Important differences include improved performance of the system when using TGRP along with lower viscosity (77.6–148.5 cP at 27 °C) and higher energy content (32.5–33.5 MJ/kg) of the bio-oil compared to conventionally produced liquids. Chemically, the TGRP bio-oils were composed largely of aromatic hydrocarbons, phenols, and nitrogenated compounds. This more stable mixture allowed for distillation of the bio-oil into fractions with higher concentrations of certain platform chemicals including phenolics and nitrogenated compounds such as pyrrole. In addition to the liquid, the biochar and noncondensable gases had improved properties.