Novel enzymes for pretreatment of macroalgal biomass

Date

2023

Abstract

Macroalgae are known to have many industrial applications, with current research efforts being placed on the potential of microalgal biomass as feedstock in production of biofuels. Marine algal biomass is rich in storage carbohydrates, alginate, laminarin and cellulose, which can be converted to fermentable sugars using appropriate enzymes, for fermentation to ethanol. In this study, bacterial isolates from the mangrove of Pagbilao, Quezon [Philippines] and water and algal samples from Burot, Calatagan, Batangas were screened for their ability to degrade alginate by alginate lyase. plate assay. Eight bacterial isolates were found to have alginate-degrading ability indicating the presence of the enzyme, alginate lyase. Optimum growth temperature, oxygen requirement, and ability to ferment sugars of the isolates were determined. All of the isolates were gram-negative and tested positive for catalase test with an optimum growth temperature of 30 deg C. Catalase test revealed that they were aerobic. Fermentation profiles were unidentical, suggesting that three of the isolates may belong to different bacterial strains. All three isolates were also capable of starch hydrolysis. Alginate lyases of the three isolates 16s, rRNA gene sequencing revealed that isolates 1b and 5 are Vibrio spp. Optimum pH, temperature and salt concentration of isolate 2p were pH 7.0, 7% NaCl and 37Cafter 36 h of incubation. Isolation and identification of laminarin-degrading microorganism and production of partially purified laminarinase of algal biomass saccharification was also done. Results showed that the partially purified laminarinase produced from Bacillus sp. was able to hydrolyze the laminarin present in the microalagae. Fermentation of the algal hydrolysate yielded only small amount of ethanol due to lack of other pre-treatment methods. However, it was observed that higher ethanol was produced in saccharification treatments using a combination of cellulase and laminarinase which implies a possible synergistic effect of the two enzymes with each other.

Language

English

Document Type

Article

Pages /Collation

62 leaves

En – AGROVOC descriptors

ALGAE; MARINE ECOLOGY; BIOMASS; ENZYMES; ALGINATES; MANGROVES; ETHANOL; ENERGY RESOURCES

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