Sediments from hydrocarbon contaminated environments were sampled and microbial communities (MC) were isolated from the sediments using special strategies depending on the desired type of MC.
One MC was isolated for the production of bioplastics (polyhydroxyalkanoates (PHAs)) that are symilar to polyetilene and polypropylene, and that are biodegradable and biocompatible. The MC were called MCPHA. The first isolation was done with acetate as substrate, and then acetate was replaced by different wastes such as the liquid product of lignocellulosic biomass pyrolysis (bio-oil) and paper sludge from a recycling paper company. The MC were characterized, and species known by their capacity to produce PHAs, and degrade hydrocarbons were found within the most abundant in the MC isolated. The PHA produced was quantified by GC-FID reaching a production between 10 to 30% when the MC were cultivated with the residues as substrate, and within 30-50% for MC that were cultivated with acetate as substrate. The PHA produced by MCPHA was extracted and characterized and it was found that it is pure polyhydroxybutyrate (PHB).
A second MC was isolated using raw lignocellulosic biomass (corn straw) as substrate. This MC, called MCB, demonstrated to be able to degrade the lignocellulosic biomass without any pre-treatment, a 50% degradation was observed in 10 days culture. The substrate was changed by paper sludge form a recycling paper company and the MCB were able to grow in presence of this residue without any pre-treatment. The Fatty Acids (FAs) produced by the MCB grown with corn straw as substrate, and grown with paper sludge as substrate were analyzed and it was found that FAs of industrial interest in cosmetics, biofuel and medicine were produced, like miristate, stearate, linoleate, heptadecanoate, etc. The MCB was characterized and species with known lignocellulose degradation activity, hydrocarbons capacity and FAs production were found.
A circular economy approach was created for the production of valuable chemicals like PHAs and FAs, using local raw material such the agricultural and industrial waste and the MC sampled in local environments.
