ABSTRACT
@#Aims:In this study, measurement of colour changes during solid state fermentation (SSF) are presented as one of the potential techniques that can be used to describe growth, complementary to other biomass estimation, such as weight of fungus, spores concentration, organic matter loss, glucosamine and enzyme activity, which is directly related to growth.Methodology and results: In this study, fungal fermentation of Aspergillus awamoriand A.oryzaeare carried out on complex heterogeneous solid media; wheat bran, soybean hull and rapeseed meal, which are constituted of various soluble and insoluble solid particles. Fermented mass was extracted using distilled water to obtain a cell free extract, which canbe determined quickly and accurately using UV-Visible spectrophotometermeasured absorbance at 300 nm. The results showed a significant correlation between colours produced from fungal SSF and the concentration of spores, weight of fungus cells, organic matter loss, glucosamine and enzyme activity. We found that the colour density proportionally increased when the studied parameters mentioned above increased.For the growth of A. awamoriand A. oryzaeon wheat bran, soybean hulls and rapeseed meal, it was confirmed that colour production was directly proportional to fungal growth. In general, colour-based methods seem to be the most promising approach for biomass estimation in SSF.Conclusions, significance and impacts of study:The theory of measuring colour changes in SSF by UV-visible spectroscopy demonstrates that the colour method gives some valuableinformation than just obtaining a visual observation or spore count to describe growth of fungal mycelium in SSF. The ideas obtained from this exercise might provide a quick and convenient method for quality control of fungal growth. The advantages of this method are that the procedure is simple to carry out, it is non-destructive and no special and expensive reagents are required and the process is very cheap.This newapproach is an important complimentation to the existing techniques especially for basic studies.
ABSTRACT
Aims: Previously described as non-favorable-microbial habitat, peat swamp forest has its own features, which are extremely acidic, poor in nutrient, water-logged and anoxic environment where rate of decomposition of plant litters is quiet slow. Interestingly, current research has proven that there is diversity of microbial communities in this ecosystem. The main objective of this study is to isolate bacteria from Pekan peat swamp forest soil that play a role in the decomposition of plant litters through cultivation on different agar-based medium. The success of isolation of bacteria from this neglected habitat could open the opportunity in unleashing the specific role of bacteria in peat swamp plant litter degradation as well as potential biotechnological application of these bacteria in lignocellulose-related industry. Methodology and results: To mimic the peat condition that is low in nutrient and comprised of plant debris, M1 and peat agar supplemented with cellulose, glucose, lignin and xylan were used. Specifically, for the isolation of actinomycetes, dry and wet heat pre-treatments were applied to the soil samples. Then, the samples were cultivated on three different agars which were oatmeal agar as well as M1 and peat agar supplemented with glucose. Enrichment method was applied in the isolation of cellulase-producing bacteria. It was found that higher number of bacteria and actinomycetes were successfully isolated from peat agar, followed by oatmeal agar and M1. In fact, more actinomycetes were isolated from soil that was treated with wet heat pre-treatment compared to dry heat pre-treatment and on peat agar compared to M1 and oatmeal agar. This finding is promising, indicating that the application of peat water in the agar-based medium is useful to mimic the actual environment of peat swamp and increase the possibility to isolate indigenous bacteria. Primary screening of isolates from samples enriched with carboxymethyl cellulose (CMC) showed positive result of decolourisation zone on Azo-CM-Cellulose agar indicating the ability of isolates to degrade cellulose compound. Conclusions, significance and impacts of study: The study indicates the effectiveness of different culture media in successful isolation of bacteria including actinomycetes. Using the enrichment method, bacteria that are able to degrade cellulose compound was successfully isolated even though it is well known that plant litter degradation in the peat swamp environment happens at very slow rates.