Utilização de caroço de manga como substrato alternativo para produção de biossurfactante
Abstract
Surfactants are amphiphilic molecules with properties of adsorption and formation of
micelles, which guarantee the ability to reduce surface tension, emulsion formation, phase
dispersion, and other purposes. However, conventional surfactants are still produced from
petroleum, which is harmful to the environment and the populations that consume it. Because
of this, biosurfactants have been the subject of studies, as they are molecules similar to synthetic
surfactants and produced by microorganisms, being biodegradable and less toxic, and for their
production renewable sources can be used, such as agro-industrial residues that in addition to
being a source of carbon it is a valuation of residual biomass. Brazil, as a large agricultural
producer, generates agro-industrial residues on a large scale, and its use as a substrate in
fermentation can significantly reduce the cost of production of biosurfactants. Within this
agricultural sector, Brazil is the seventh world producer of mango and its residual biomass has
considerable amounts of oils and sugars to be used in the production of biosurfactants. Thus,
the production of biosurfactant by autochthonous bacteria isolated from self-fermented residual
mango biomass and by Pseudomonas aeruginosa was evaluated, using dehydrated, ground, and
pre-treated mango seed as substrate. The mango seed was characterized with lipid content of
3.25% and in the pre-treatment, by autoclave, it released 67 ± 0.01 mg/g of total reducing
sugars. The isolate identified as Brevibacillus borstelensis was the only one capable of
producing emulsifying agents, presenting a maximum emulsion index of 48.65% with glucose,
however, the P. aeruginosa strain showed the best results, with an emulsion index of 57.7%
with glucose and positive results in the droplet collapse, oil displacement and hydrocarbon
plaque tests, which was selected for the biosurfactant production assays with the pre-treated
mango seed. Through experimental planning, it was possible to optimize the production of
biosurfactant at pH 6, with 3 g/L of substrate and without the addition of soybean oil and
glycerol, reaching a maximum emulsion index of 66.86%, with 9, 16% higher than glucose
control. The extracted biosurfactant showed a negative ionic charge and belongs to the class of
glycolipids. Therefore, pre-treated mango seed can be an alternative substrate for biosurfactant
production by Pseudomonas aeruginosa
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