Flocculation phenomenon of a mutant flocculent Saccharomyces cerevisiae strain: Effects of metal ions, sugars, temperature, pH, protein-denaturants and enzyme treatments

The flocculation mechanism of a stable mutant flocculent yeast strainSaccharomyces cerevisiae KRM-1 was quantitatively investigated for potential industrial interest. It was found that the mutant flocculent strain was NewFlo phenotype by means of sugar inhibition test. The flocculation was completely inhibited by treatment with proteinase K, protein-denaturants and carbohydrate modifier. The absence of calcium ions significantly inhibited the flocculation, indicating that Ca2+ was specifically required for flocculation. The flocculation was stable when temperature below 70°C and pH was in the range of 3.0 - 6.0. The flocculation onset of the mutant flocculent strain was in the early stationary growth phase, which coincided with glucose depletion in the batch fermentation for the production of ethanol from kitchen refuse medium. The results are expected to help develop better strategies for the control of mutant flocculent yeast for future large-scale industrial ethanol fermentation

Production of L(+)-Lactic Acid from Mixed Acid and Alkali Hydrolysate of Brown Seaweed

The species of brown seaweeds, Laminaria japonica is commercially cultivated in Japan. Mannitol and uronic acid were the main component of mono sugar produced from the saccharification of L. japonica which hydrolysed with H2SO4 or NH4OH. The mannitol concentration of L. japonica (5w/v%) hydrolysate using 0.5v/v% H2SO4 or 1v/v% NH4OH were 15.84g/L and 13.87g/L, respectively. Hydrolysates from both acid and alkali hydrolysis were mixed together for neutralization as well as to obtain higher mannitol concentration of 15.18g/L. Among the mono sugar in the hydrolysate, Mannitol was the main substrate for the lactic acid fermentation by Lactobacillus rhamnosus. L(+)-Lactic acid with 97.9% of optical purity was successfully produced at the yield of 14.42g/L (Yp/s = 94.99%)

Potential Use of Gelidium amansii Acid Hydrolysate for Lactic Acid Production by Lactobacillus rhamnosus

Galactose and glucose are the main monosaccharides produced from the saccharification of Gelidium amansii. They were hydrolysed with 3 % (by volume) H2SO4 at 140 °C for 5 min and obtained at concentrations of 19.60 and 10.21 g/L, respectively. G. amansii hydrolysate (5 %, by mass per volume) was used as a substrate for L(+)-lactic acid production by Lactobacillus rhamnosus. The maximum lactic acid yield (YP/S) was 42.03 % with optical purity of 84.54 %. Lactic acid produced from G. amansii hydrolysate can be applicable, among others, for the production of lactic acid esters, like ethyl or methyl lactate, and disinfectant in seaweed cultivation

Characteristics of leachate from selected MSW landfills and relationships with river water chemistry.

Leachate from three different landfills was characterized and its relationship with river water chemistry was evaluated to gain information for further improvement of current leachate management. The leachate from both active uncontrolled and closed controlled landfills was in methanogenic phase, while active controlled landfill was in acidic phase. There could be a relationship between leachate from uncontrolled landfill and river water chemistry, mainly as NH3-N, TOC and Fe. Whereas treatment of organic NH3-N and metals such as Fe, Mn, Cu, Cd and Cr was necessary as leachate in active controlled landfill high in organics, ammonia and pyrite oxidation was expected in the nearby stream. In addition denitrification of leachate might be required at closed controlled landfill. Management of landfill leachate is considered complicated and challenging due to the variation in its composition and the environmental problems associated with the pollutants produced. This variation is often attributed to the age of the landfill, amount and type of waste disposed, biological decomposition of waste, solubilization of soluble salts in waste, climate and moisture content in waste itself (Tchobanogolous et al., 1993). Moreover, leachate in Malaysia is highly heterogeneous due to the fact that wastes are not separated at source. Thus, leachate characteristics could be specific for each landfill and its information is very important in determining a suitable treatment method. Unfortunately, this basic information is still scarce in the country as monitoring of leachate characteristics are expensive and time-consuming

Baseline study of methane emission from anaerobic ponds of palm oil mill effluent treatment

The world currently obtains its energy from the fossil fuels such as oil, natural gas and coal. However, the international crisis in the Middle East, rapid depletion of fossil fuel reserves as well as climate change have driven the world towards renewable energy sources which are abundant, untapped and environmentally friendly. Malaysia has abundant biomass resources generated from the agricultural industry particularly the large commodity, palm oil. This paper will focus on palm oil mill effluent (POME) as the source of renewable energy from the generation of methane and establish the current methane emission from the anaerobic treatment facility. The emission was measured from two anaerobic ponds in Felda Serting Palm Oil Mill for 52 weeks. The results showed that the methane content was between 35.0% and 70.0% and biogas flow rate ranged between 0.5 and 2.4 L/min/m2. Total methane emission per anaerobic pond was 1043.1 kg/day. The total methane emission calculated from the two equations derived from relationships between methane emission and total carbon removal and POME discharged were comparable with field measurement. This study also revealed that anaerobic pond system is more efficient than open digesting tank system for POME treatment. Two main factors affecting the methane emission were mill activities and oil palm seasonal cropping

Improved anaerobic treatment of palm oil mill effluent in a semi-commercial closed digester tank with sludge recycling and appropriate feeding strategy

Anaerobic treatment of palm oil mill effluent (POME) in a semi-commercial closed digester tank with sludge recycling was studied using different feeding strategies; one fixed at every three hour and another at every six hour. The organic loading rate (OLR) was increased step-wise and stopped once inhibition on methane production occurred. The chemical oxygen demand (COD), feeding rate, hydraulic retention time (HRT),OLR, and sludge recycling ratio were measured. Performance was based on the COD removal efficiency and methane yield, while stability was assessed in terms of total volatile fatty acids (VFA) accumulation, total VFA-to-alkalinity ratio (VFA:Alk) and food-to-microorganisms ratio (F/M ratio). The feeding strategies, at every three hour and six hour, gave satisfactory COD removal efficiency of higher than 90%, but the latter feeding strategy gave a more stable process with total VFA concentration recorded below 500 mg L-1 and VFA:Alk ratio of less than 0.3 at maximum OLR of 6.0 kgCOD m-3 d-1. The treatment period could also be extended up to 100 days without any obvious problems

A Useful Biomass Component for Simple Fabrication of the Honeycomb Poly(L-lactide) Film

This concept is the development of useful material based on biomass such as a poly(L--lactide)[PLLA] with new added-value to extend applications. PLLA, which is an attractive raw material produced from renewable resources, has received much attention for applications in bioabsorbable and biodegradable materials. However, PLLA is not utilized well for practical use. This paper has explored an additive compound, which is a biocompatible, to facilitate a regular patterned porous film from PLLA to provide a valuable material. The method we adopted was to form a regular pattern on polymer film containing a surfactant in order to help the amphiphilic polymer to migrate at the interface between the organic solvent and the water droplets as the water-assisted formation method. To give the regular patterned porous film, some compounds from biomass were used for the water-assisted formation method. As surfactants in PLLA solutions, the experimental results showed the effectiveness of soy-bean oil. The pore size and surface morphology on the film can be controlled through the moisture condition, the PLLA concentration, and the molecular weight of PLLA

Measuring organic carbon, nutrients and heavy metals in rivers receiving leachate from controlled and uncontrolled municipal solid waste landfills

Since landfilling is the common method of waste disposal in Malaysia, river water is greatly exposed to the risk of contamination from leachate unless proper leachate management is carried out. In this study, leachates from three different types of landfills, namely active uncontrolled, active controlled and closed controlled, were characterized, and their relationships with river water chemistry were examined monthly for a year. The influence of leachate on river water chemistry from each type of landfill depended on many factors, including the presence of a leachate control mechanism, leachate characteristics, precipitation, surface runoff and the applied treatment. The impact of leachate from an active uncontrolled landfill was the highest, as the organic content, NH(4)(+)-N, Cd and Mn levels appeared high in the river. At the same time, influences of leachate were also observed from both types of controlled landfills in the form of inorganic nitrogen (NH(4)(+)-N, NO(3)(-)-N and NO(2)(-)-N) and heavy metals (Fe, Cr, Ni and Mn). Improper treatment practice led to high levels of some contaminants in the stream near the closed controlled landfill. Meanwhile, the active controlled landfill, which was located near the coastline, was exposed to the risk of contamination resulting from the pyrite oxidation of the surrounding area

Residual palm oil recovery from empty fruit bunches and palm oil mill effluent

Oil extraction rate (OER) is a universal indicator to measure the actual amount of oil obtained from the oil palm fresh fruit bunches (OPFFB) at palm oil mills. The maximum OER from a ripe oil palm fresh fruit bunch was estimated to be 30%. Over the past few decades, the OER has not made significant improvement and the reasons always being associated with soil, climate, oil palm species and age, poor milling operation and machine inefficiency. Not many efforts have been given to determine the oil loss in the palm oil wastes and wastewater as well as to recover it. The proof is over the years, the palm oil industry has not changed much in terms of its processing and design. Most of the process and machinery design in the mill are still using the same technology since 50 years ago. Therefore, there is an urgent need to provide a re-engineering solution for some of the processing especially to recover and reuse the residual oil. Palm oil mill effluent (POME) and oil palm empty fruit bunch (OPEFB) are main by-products generated from milling process, which contain high amount of residual oil. For instance, about 0.6 – 0.7 % residual oil was found in POME and about 15 – 28 % (dried weight basis) was found on OPEFB spikelet. High pressure water spray system and micro/nano-bubble system are eco-friendly combination method that can be employed to remove oil from OPEFB and separate oil from aqueous solution (oil-water obtained from OPEFB and POME), respectively. The aim of this research work is to evaluate the recovery and utilizing residual crude palm oil from waste streams of palm oil milling process for the production of any value added product (e.g. biodiesel)

Selective component degradation of oil palm empty fruit bunches (OPEFB) using high-pressure steam

In order to accelerate the bioconversion process of press-shredded empty fruit bunches (EFB), the effect of high-pressure steam pre-treatment (HPST) in degrading the lignocellulosic structure was investigated. HPST was carried out under various sets of temperature/pressure conditions such as 170/0.82, 190/1.32, 210/2.03, and 230 °C/3.00 MPa. It was noted that after HPST, the surface texture, color, and mechanical properties of the treated EFB had obviously altered. Scanning electron micrographs of the treated EFB exhibited effective surface erosion that had occurred along the structure. Moreover, the Fourier transform infrared and thermogravimetric analyses showed the removal of silica bodies and hemicellulose ingredients. X-ray diffraction profiles of the treated EFB indicated significant increases in crystallinity. These results reveal that HPST is an effective pre-treatment method for altering the physicochemical properties of the EFB and enhancing its biodegradability characteristics for the bioconversion process