Microbial diversity in disturbed and undisturbed peat swamp forest and isolation of cyanobacteria

Microbial diversity from disturbed and undisturbed peat swamp forest obtained from next generation sequencing. Through this analysis, genera cyanobacteria is being compared with isolated cyanobacteria from both environmments which is extremely acidic. For the future study, this genera has ability as biofertilizer in acidic soil for plantations

Induction condition of secondary metabolites production in soil actinomycetes, rhodococcus jostii RHA1

Rhodococcus jostii RHA1 is a potent polychlorinated biphenyl-degrading soil actinomycete that catabolizes a wide range of compounds and represents a genus of considerable chemical and industrial interest. Genome of RHA1 contains nonribosomal peptide synthase (NRPS) genes, and polyketide synthase (PKS) genes, providing evidence that RHA1 harbor an extensive secondary metabolism as same as other actinomycetes. To elucidate R. jostii RHA1 may produce any kinds of secondary metabolites, induction condition of these secondary metabolite production genes were investigated. Type I, type III, PKS-NRPS hybrid located on chromosome, and NRPSs located on plasmid were typically induced on solid medium with specific nutrient or environment condition. On the other hands, type II PKSs located on chromosome were mainly induced on liquid medium with specific condition. These results indicated that secondary metabolites induced on specific condition on solid or liquid medium by RHA1 might play a key role of surviving under severe environmental condition

Experimental analysis on structure-borne noise in an enclosure

This paper present the experimental analysis conducted on a structure-borne noise in a rectangular enclosure prototype made by joining of sheet aluminum metal and plywood. The study is significant as the structural noise could cause annoyance and dizziness thus by deepening the comprehension on the structure-borne noise, the noise problem could be overcome. In this study, modal analysis is carried out to seek the structure’s behavior in order to identify the characteristics of enclosure in frequency domain ranging from 1 Hz to 100 Hz. Here, numbers of modes are identified and the characteristic of mode shape is categorized. Modal experiment is used to diagnose the structural behavior while microphone is used to diagnose the sound. Spectral testing is performed on the enclosure and it is acoustically excited using shaker and as it vibrates, the vibrational and noise responses sensed by tri-axis accelerometer and microphone sensors are recorded respectively. The modal modes extracted from the experiment are validated by simulation performed using MSC NASTRAN/PATRAN software. From developed prototype, the structural behavior can be diagnosed and the mode shape can be determined. In the end of the study, the relation and major contribution of the structural and sound in the enclosure can be identified from the observation of both spectrums

Isolation and characterisation of copper leaching microbes from sanitary landfill for e-waste bioleaching

Electronic waste has been the fastest increasing waste generated globally and is predicted to surpass 111 million tons per year by 2050. This trend is concerning, not just due to the growing volume but also due to its high composition of heavy metal elements, leading to potential environmental pollution if not managed properly. However, this issue opens a new prospect in material acquisition through the concept of urban mining via the metal extraction from electronic waste. A conventional method of extraction, i.e., chemical leaching, possesses harmful environmental impact with the production of its residual leachate. Thus, an alternative extraction technique is proposed, known as bioleaching, in which the microbial activity from bacteria mobilized metal into a more soluble form. In this study, bacterial strains were isolated from Malaysia sanitary landfill for bioleaching of copper from waste printed circuit boards (wPCB) with minimal mechanical pre-processing procedure. They were grown in low pH media to utilize their activity for copper bioleaching from the wPCB. Four bacterial strains were successfully isolated. Using 16S rRNA gene sequencing, the isolates were identified as Bacillus sp. strain SE, Bacillus sp. strain SC, Lysinibacillus sp. strain SE2, and Oryzobacter terrae strain S1A. All the isolates showed appropriate bioleaching ability, with strain SC demonstrated the highest copper extraction with up to 23.36 ppm through the two-step bioleaching process. This strain was further evaluated using a copper strip to observe the actual copper extraction and demonstrated a total of 0.80 ±0.02 mg/g copper recovery. These results suggest that copper bioleaching of wPCB is viable as a standalone process

Enhancement of astaxanthin accumulation using black light in Coelastrum and Monoraphidium isolated from Malaysia

Microalgae are important microorganisms which produce potentially valuable compounds. Astaxanthin, a group of xanthophyll carotenoids, is one of the most powerful antioxidants mainly found in microalgae, yeasts, and crustaceans. Environmental stresses such as intense light, drought, high salinity, nutrient depletion, and high temperature can induce the accumulation of astaxanthin. Thus, this research aims to investigate the effect of black light, also known as long-wave ultraviolet radiation or UV-A, as a stressor on the accumulation of astaxanthin as well as to screen the antioxidant property in two tropical green algal strains isolated from Malaysia, Coelastrum sp. and Monoraphidium sp. SP03. Monoraphidium sp. SP03 showed a higher growth rate (0.66 day-1) compared to that of Coelastrum sp. (0.22 day-1). Coelastrum sp. showed significantly higher accumulation of astaxanthin in black light (0.999 g mL culture-1) compared to that in control condition (0.185 g mL-1). Similarly, Monoraphidium sp. SP03 showed higher astaxanthin content in black light (0.476 g mL culture-1) compared to that in control condition (0.363 g mL culture-1). Coelastrum sp. showed higher scavenging activity (30.19%) when cultured in black light condition, indicating a correlation between the antioxidant activity and accumulation of astaxanthin. In this study, black light was shown to possess great potential to enhance the production of astaxanthin in microalgae

Effect of Office Design Characteristics and Anthropometrics on Thermal Comfort in Malaysian Universities Air-Conditioned Buildings

Apart from indoor environmental and personal factors, contextual factors have significantly influenced several thermal comfort studies. In air-conditioned spaces, thermal comfort is conveniently attainable by adjusting the temperature settings, but indoor design elements might alter thermal perceptions and provide adaptive opportunities. This study examines the influence of office design characteristics and anthropometrics on thermal comfort parameters and perceptions. Nineteen university offices in Kuala Lumpur and Shah Alam, comprised of twelve shared and seven private spaces, were investigated, and 628 responses were collected from 42 participants with even gender distributions. The results showed that room occupancy and size were statistically significant with Griffiths’ comfort temperature. Offices with five or more people had lower mean comfort temperature (24.1 ℃) than private offices (25.0 ℃). The mean comfort temperature in offices larger than 80 m2 was 23.7 ℃ with warmer thermal preference, while offices smaller than 40 m2 were approximately one-degree Celsius higher. Offices with no shading device, window blinds opened, and tiled floorings had mean comfort temperatures higher than 25.0 ℃. The findings also indicated that offices with more than a 60% glazing ratio have a slightly higher mean comfort temperature at 24.9 ℃. The thermal sensation during closed blinds was much cooler than opened ones. The anthropometry of the human body impacts how heat is regulated; thus, respondents with higher Body Mass Index (BMI) and above-average body surface area (higher than 1.7 m2) had significantly lower comfort temperatures and preferred more humid surroundings. Mean comfort temperature was statistically significant with BMI with a noticeable difference between underweight (25.1 ℃), normal (24.5 ℃), and obese (23.9 ℃) BMIs. In this study, it is recommended that BMI be considered when positioning occupants in shared offices, and window blinds are an integral shading device for adjusting indoor thermal comfort levels

Chemical-free extraction and identification of sugar components from oil palm biomass through a hydrothermal process

Purpose: The aims of this research were to extract sugar-based products from oil palm biomass, oil palm fronds (OPFs) and oil palm fruit pressed fibers (FPFs) via a hydrothermal process using accelerated solvent extraction and to identify the sugar content of the aqueous phase at different temperatures and reaction times. Methods: The liquid products obtained from accelerated solvent extraction were further analyzed for the total sugar content and number of sugar components using the phenol-sulfuric acid method and gas chromatography–mass spectrometry. Results: The highest sugar contents of the FPF and OPF samples were detected at 180 °C and at reaction times of 10 min and 30 min. Further extension of the reaction time at 180 °C showed that the optimal hydrolysis durations were 50 min for FPFs and 40 min for OPFs. These results may have been due to the physical structures and compositions of the samples. Analysis of the qualitative data indicated the presence of more sugar components in the FPF sample than in the OPF sample. This result was possibly due to the presence of unique and unidentified sugar components in the OPF sample. Conclusions: Hydrothermal processing via accelerated solvent extraction is a promising solution for the hydrolysis and fractionation of oil palm biomass to extract total sugars. Graphic Abstract: [Figure not available: see fulltext.]

Production of Bio-Coke from spent mushroom substrate as a sustainable solid fuel

Spent mushroom substrate (SMS), defined as the residual biomass after mushroom cultivation, has been known to cause serious pollution, especially river pollution, as it is produced in large quantities and has been disposed of without consideration of the environment. Thus, there is growing interest in converting this biomass waste into Bio-Coke as an alternative solid fuel to be used in a boiler to generate steam for mushroom substrate pasteurization. This study analyzes the physical characteristics of Bio-Coke conversion from SMS in Malaysia, and it was found to have better physical characteristics than other types of conventional biomass fuel. The results indicate that Bio-Coke from SMS at a formation temperature of 170 °C had an apparent density of 1.397 g/cm3 and a combustion period of 1890 s. Its maximum compressive strength at room temperature (25 °C) and 700 °C was 105.2 and 5.302 MPa, respectively, which is ideal for a biomass solid fuel. Its high apparent density and mechanical strength provide evidence that SMS Bio-Coke is structurally robust and can remain intact when compressed at high pressure and burned at high temperature in a boiler. Thus, the use of SMS Bio-Coke presents itself as a potential strategy for biomass waste management in Southeast Asia, particularly Malaysia