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Palm oil mill effluent (POME) is one of the main agro-industrial wastewaters in Malaysia. Highly polluting POME is a serious threat to the environment. In recent years, the methods used to treat POME are inefficient and complex in terms of cost or environmental preservation. The main object of this research is to propose a single reactor system (SRS) obtained from POME wastewater discharge as a promising low-cost treatment and high-energy method for harvesting the fermentable sugar by applying acid–base–enzyme pretreatment and hydrolysis of POME by locally produced cellulase enzymes to enhance biofuel production. Several experiments were conducted to produce fermentable sugars through the statistical methods, including the characterization of POME, acid-base pretreatment, and enzymatic hydrolysis process for reducing sugar production. The one-factor-at-a-time (OFAT) results showed that the highest reducing sugar yield, 23.5 mg/mL of POME, was achieved by enzymatic hydrolysis in an SRS without having a separation and purification. Based on OFAT performance, optimization of two factors such as substrate concentration (total suspended solids, TSS %w/v) and enzyme loading (μmol/min) was carried out by applying face-centered central composite design (FCCCD) under the response surface methodology (RSM) to develop a second-order regression model. The optimum reducing sugar production was 26.6 mg/mL (53.14%) with the conditions of 5% w/v, TSS, and 80 μmol/min/mL of the enzyme dose. In addition, the results of this research can be further considered in biofuel production using other wastewaters to enhance biofuel production as well as wastewater treating functions and minimize the negative environmental impacts. [ABSTRACT FROM AUTHOR]

The utilization of lignocellulose biomass as an alternative source of renewable energy production via green technology is becoming important, and is in line with sustainable development goal initiatives. Lignocellulolytic bacteria, such as Bacillus spp., can break down biomass by producing hydrolytic enzymes, which are crucial in the successful conversion of biomass or lignocellulosic material into renewable energy. This information gave rise to this study, where municipal solid waste sediments of a sanitary municipal solid waste landfill were sampled and screened, and lignocellulolytic bacteria were isolated and characterized. Samples were taken from four different locations at the Pulau Burung landfill site in Malaysia. Lignin and starch were used as sources of carbon to identify potential bacteria that exhibit multi-enzymatic activity. The growth rate and doubling time of bacterial isolates in lignin and starch were taken as the criteria for selection. Eleven bacterial isolates were screened for cellulase activity using iodine and Congo red dyes. The cellulase activity of these isolates ranged from 0.8 to 1.7 U/mL. We carried out 16S rRNA gene sequencing to identify the phyla of the selected bacterial isolates. Phylogenetic analysis was also conducted based on the 16S rRNA sequences of the bacterial isolates and related Bacillus species, and a tree was generated using the Neighbor-Joining method. In this study, Bacillus proteolyticus, Bacillus Sanguinis, Bacillus spizizenii, Bacillus paramycoides, Bacillus paranthracis and Neobacillus fumarioli were identified as promising bacteria capable of expressing lignocellulolytic enzymes and degrading the lignocellulosic biomass present in municipal solid waste. [ABSTRACT FROM AUTHOR]

The oil palm biomass produced by plantations and mills in Malaysia is the largest contributor to the nation's agro-waste, with the oil palm leaves (OPL) topping the list. Nevertheless, the surplus of OPL might have applicability as the substrate for cultivating lignocellulolytic bio-degraders. Ipso facto, this study employed raw OPL as the carbon source for cultivating Trichoderma harzianum under solid-state fermentation (SSF). Optimizing the SSF process using the Taguchi orthogonal design to produce endoglucanase (CMCase) successfully established the optimal fermentation conditions: 7.00 × 108 spore/g inoculum size, 50% moisture content, pH 12 Mandel's medium, with 3-day incubation at 40°C. The crude enzyme cocktail exhibited the corresponding maximum activity of 417.49 ± 6.61 U/g CMCase. The SSF process parameters significantly affected the enzymatic activities, namely, moisture content, inoculum size, and initial pH (p-value < 0.05). It can be construed that the high extracellular CMCase activity of the T. harzianum crude enzyme cocktail could be useful in accelerating the saccharification of cellulose for biofuel-and nanocellulose production. [ABSTRACT FROM AUTHOR]

Bacteria are present in stingless bee nest products. However, detailed information on their characteristics is scarce. Thus, this study aims to investigate the characteristics of bacterial species isolated from Malaysian stingless bee, Heterotrigona itama, nest products. Honey, bee bread and propolis were collected aseptically from four geographical localities of Malaysia. Total plate count (TPC), bacterial identification, phenotypic profile and enzymatic and antibacterial activities were studied. The results indicated that the number of TPC varies from one location to another. A total of 41 different bacterial isolates from the phyla Firmicutes, Proteobacteria and Actinobacteria were identified. Bacillus species were the major bacteria found. Therein, Bacillus cereus was the most frequently isolated species followed by Bacillus aryabhattai, Bacillus oleronius, Bacillus stratosphericus, Bacillus altitudinis, Bacillus amyloliquefaciens, Bacillus nealsonii, Bacillus toyonensis, Bacillus subtilis, Bacillus safensis, Bacillus pseudomycoides, Enterobacter asburiae, Enterobacter cloacae, Pantoea dispersa and Streptomyces kunmingensis. Phenotypic profile of 15 bacterial isolates using GEN III MicroPlateTM system revealed most of the isolates as capable to utilise carbohydrates as well as amino acids and carboxylic acids and derivatives. Proteolytic, lipolytic and cellulolytic activities as determined by enzymatic assays were detected in Bacillus stratosphericus PD6, Bacillus amyloliquefaciens PD9, Bacillus subtilis BD3 and Bacillus safensis BD9. Bacillus amyloliquefaciens PD9 showed broad-spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria in vitro. The multienzymes and antimicrobial activities exhibited by the bacterial isolates from H. itama nest products could provide potential sources of enzymes and antimicrobial compounds for biotechnological applications. [ABSTRACT FROM AUTHOR]

White root disease caused by Rigidoporus microporus is the most devastating disease in majority of the rubber growing countries, including Malaysia. This study aimed to screen and decipher the mechanisms involved in the biocontrol agents responsible for the inhibition of R. microporus. Among 16 fungal isolates, Trichoderma spp. showed promising results with the highest percent of inhibition shown by Trichoderma asperellum (80.54%). Scanning electron microscopy study revealed coiling of hyphae by Trichoderma species against R. microporus. T. asperellum has demonstrated a maximum inhibition in both volatile and non-volatile metabolite tests with its 75% culture filtrate on PDA plate was observed to cause abnormal morphological character in R. microporus. All Trichoderma species were shown to produce hydrolytic enzymes (chitinase, cellulase and β-1,3-glucanase) and they were active siderophore producers. Present study demonstrated the possible mechanisms involved and responsible for successful inhibition of R. microporus under in vitro condition especially by T. asperellum. [ABSTRACT FROM AUTHOR]

Centella asiatica (L.) or known locally as Pegaga has been recognized by Ministry of Agriculture (MoA) Malaysia as one of the top 10 the best herbs in Malaysia. Considering its beneficial advantages, the varieties of C. asiatica in Malaysia have been compared and further investigated for its potential to produce essential oil. In this study, the bioactive compounds, total phenolic content (TPC) and antioxidants activity from different varieties of Centella asiatica (L.) known as Pegaga Kampung, Pegaga Nyonya and Pegaga Salad from Malaysia and Pegaga Thailand have been determined followed by the extraction of essential oil using hydro-distillation (HD) and hydro-distillation with enzyme assisted (HDEA). Findings showed that Pegaga Kampung had the highest asiaticoside content of 0.259 mg/g, TPC of 9.22 mg GAE/g and DPPH radical scavenging activity (DPPH*) of 76.88% in leaf, 67.77% in petiole, and 60.37% in root as compared to other varieties of C. asiatica. Extraction of essential oils from Pegaga Kampung using HDEA with 40 FPU/g substrate of cellulase produced the highest yield of 1.01%. A higher TPC of 107.05 mg GAE/100 g was detected in essential oils extracted using HDEA with 10 FPU/g substrate of cellulase, whereas the highest DPPH* of 19.02% was found in essential oil using HD. [Display omitted] • To examine characteristics of different varieties of C. asiatica including one variety of C. asiatica from Thailand based on the concentration of asiaticoside, total phenolic content (TPC), and antioxidant properties, as well as their morphological analysis. • From the study, it was found that Pegaga Kampung showed a higher asiaticoside and TPC concentration, thus it has been used for the extraction of essential oil using hydrodistillation (HD) and HD with enzyme assisted (HDEA) at different substrate and enzymes loading. • HDEA had increased the yield of essential oil and the TPC concentration, while HD had increased the antioxidant activity. • This study concluded the superior variety of C. asiatica , which is Pegaga Kampung and HDEA is able to extract essential oil from C. asiatica with higher yield. [ABSTRACT FROM AUTHOR]