RESUMO

Gibberellic acid (GA3) is a natural hormone present in some plants used in agricultural formulations as a growth regulator. Currently, its production on an industrial scale is performed by submerged fermentation using the fungus Gibberella fujikuroi, which is associated with low yields, leaving the purification stages with high costs. An alternative is solid-state fermentation (SSF), which makes it possible to obtain higher concentrations of product using low-cost substrates, such as agroindustrial by-products. This research investigated the use of raw rice bran (RRB) and barley malt residue (BMR) as substrates for GA3 production by the fungus Gibberella fujikuroi. Through two statistical designs, the effect of moisture (50 to 70 wt.%) and medium composition (RRB content between 30 and 70 wt.% to a mass ratio between RRB and BMR) was first evaluated. Using the best conditions previously obtained, the effect of adding glucose (carbon source, between 0 and 80 g·L-1) and ammonium nitrate-NH4NO3-(nitrogen source, between 0 and 5 g·L-1) on GA3 productivity was analyzed. The best yield was obtained using 30 wt.% RRB and 70 wt.% BMR for a medium with 70 wt.% of moisture after 7 days of process. It was also found that higher concentrations of NH4NO3 favor the GA3 formation for intermediate values of glucose content (40 g·L-1). Finally, a kinetic investigation showed an increasing behavior in the GA3 production (10.1 g·kg of substrate-1 was obtained), with a peak on the seventh day and subsequent tendency to stabilization.

Assuntos

RESUMO

Butia capitata endocarp (BCE) is a biomass residue with the potential to produce a wide variety of bio-products. The processing of BCE in a sequential process of subcritical water hydrolysis (SWH) and hydrothermal liquefaction (HTL) was investigated to obtain fermentable sugars, platform chemicals, bio-oil, and biochar. The SWH was evaluated at 230 and 260 °C and solvent: feed mass ratios (R) of 10 and 20 for the production of fermentable sugars and platform chemicals. The solid residue from SWH was sequentially submitted to the HTL at 330 and 360 °C for bio-oil and biochar production. The results were analyzed by comparing the sequential (SWH/HTL) and individual (HTL only) processes. The highest yields of fermentable sugars (5.26 g/ 100 g BCE) were obtained for SWH at 260 °C and R-20 with higher contents of xylose (2.64 g/100 g BCE) and cellobiose (1.75 g/100 g BCE). The highest yields of platform chemicals (2.44 g/100 g BCE) were obtained for SWH at 260 °C and R-10 with higher contents of acetic acid (1.78 g/100 g BCE) and furfural (0.54 g/100 g BCE). The highest yield of bio-oil (25.30 g/100 g BCE) occurred in HTL individual process at 360 °C and R-20. Sequential process SWH/HTL showed a decrease in bio-oil yield but maintained a similar biochar yield compared to HTL, in addition to the production of fermentable sugars and platform chemicals.

RESUMO

This work investigates the use of blends of edible and nonedible raw materials as an alternative feedstock to fatty acid methyl esters (FAME) production through enzymatic catalysis. As biocatalyst, liquid lipase from Thermomyces lanuginosus (Callera™ Trans L), was used. Under reaction conditions of 35 °C, methanol to feedstock molar ratio of 4.5:1 and 1.45% of catalyst load, the best process performance was reached using 9% of water concentration in the medium-yield of 79.9% after 480 min of reaction. In terms of use of tallow mixed with soybean oil, the best yield was obtained when 100% of tallow was used in the process-84.6% after 480 min of reaction-behavior that was associated with the degree of unsaturation of the feedstock, something by that time, not addressed in papers of the area. The results show that tallow can be used as an alternative to FAME production, catalyzed by soluble lipase.

Assuntos