Homofermentative lactic acid-and cellulase-secreting Oryctes rhinoceros larval gut bacterial strains for lactic acid production
Global demand for lactic acid (LA) has increased significantly in recent years, thus, prompting increased interest in utilising lignocellulosic waste biomass for its production. This study investigated the relationship between cellulase activity and LA production by lactic acid bacteria (LAB) isolat...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | en |
| Published: |
Penerbit Universiti Kebangsaan Malaysia
2025
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| Online Access: | http://journalarticle.ukm.my/26513/1/SSS%206.pdf http://journalarticle.ukm.my/26513/ https://www.ukm.my/jsm/english_journals/vol54num11_2025/contentsVol54num11_2025.html |
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| Summary: | Global demand for lactic acid (LA) has increased significantly in recent years, thus, prompting increased interest in utilising lignocellulosic waste biomass for its production. This study investigated the relationship between cellulase activity and LA production by lactic acid bacteria (LAB) isolated from the gut of rhinoceros beetle (Oryctes rhinoceros) larvae. Out of 11 LAB strains tested, three isolates namely L5-5, L2a-1 and L3-2 were observed to exhibit good growth using glucose as substrate and were able to obtain final LA concentrations of 9.04 g/L, 9.26 g/L and 9.34 g/L, respectively. These strains were further screened for cellulolytic activity at various temperatures and pH levels using a carboxymethyl cellulose (CMC) assay and were identified as Enterococcus thailandicus through 16S rDNA sequencing. Optimal enzyme activity at 45 °C for strain L5-5 was 0.42 U/mL, L2a-1 was 0.61 U/mL, and L3-2 was 0.62 U/mL. Notably, the strong cellulolytic activity was positively correlated with the elevated LA production. These LAB strains could tolerate a broad temperature range of 30 to 50 °C, salt concentrations of 2.5 to 10 % (w/v), furfural concentration of up to 1% (v/v), and pH levels between 4.5 and 9.0. The findings highlighted the potential of LAB isolates from O. rhinoceros larval gut as viable candidates for LA production in industrial applications. |
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