Purification and Characterization of Strong Simultaneous Enzyme Production of Protease and α-Amylase from an Extremophile-Bacillus sp. FW2 and Its Possibility in Food Waste Degradation

Microbial enzymes such as protease and amylase are valuable enzymes with various applications, widely investigated for their applications in degradation of organic waste, biofuel industries, agricultural, pharmaceuticals, chemistry, and biotechnology. In particular, extremophiles play an important role in biorefinery due to their novel metabolic products such as high value catalytic enzymes that are active even under harsh environmental conditions. Due to their potentials and very broad activities, this study isolated, investigated, and characterized the protease- and amylase-producing bacterial strain FW2 that was isolated from food waste. Strain FW2 belongs to the genus Bacillus and was found to be closest to Bacillus amyloliquefaciens DSM 7T with a similarity of 99.86%. This strain was able to degrade organic compounds at temperatures from −6 °C to 75 °C (but weak at 80 °C) under a wide pH range (4.5–12) and high-salinity conditions up to 35% NaCl. Maximum enzyme production was obtained at 1200 ± 23.4 U/mL for protease and 2400 ± 45.8 U/mL for amylase for 4 days at pH 7–7.5, 40–45 °C, and 0–10% NaCl. SDS-PAGE analysis showed that the molecular weights of purified protease were 28 kDa and 44 kDa, corresponding to alkaline protease (AprM) and neutral protease (NprM), respectively, and molecular weight of α-amylase was 55 kDa. Degradation food waste was determined after 15 days, observing a 69% of volume decrease. A potential commercial extremozyme-producing bacteria such as strain FW2 may be a promising contributor to waste degradation under extreme environmental conditions.

Bacterial Succession during Vermicomposting of Silver Wattle (Acacia dealbata Link)

Vermicomposting is the process of organic waste degradation through interactions between earthworms and microbes. A variety of organic wastes can be vermicomposted, producing a nutrient-rich final product that can be used as a soil biofertilizer. Giving the prolific invasive nature of the Australian silver wattle Acacia dealbata Link in Europe, it is important to find alternatives for its sustainable use. However, optimization of vermicomposting needs further comprehension of the fundamental microbial processes. Here, we characterized bacterial succession during the vermicomposting of silver wattle during 56 days using the earthworm species Eisenia andrei. We observed significant differences in α- and β-diversity between fresh silver wattle (day 0) and days 14 and 28, while the bacterial community seemed more stable between days 28 and 56. Accordingly, during the first 28 days, a higher number of taxa experienced significant changes in relative abundance. A microbiome core composed of 10 amplicon sequence variants was identified during the vermicomposting of silver wattle (days 14 to 56). Finally, predicted functional profiles of genes involved in cellulose metabolism, nitrification, and salicylic acid also changed significantly during vermicomposting. This study, hence, provides detailed insights of the bacterial succession occurring during vermicomposting of the silver wattle and the characteristics of its final product as a sustainable plant biofertilizer.

The selection of laccase producing polypores fungi and inducer addition on the degradation of batik waste

Research on the selection of laccase producing polypores fungi and inducer addition on the degradation of batik waste has been carried out. The objectives of this study were to obtain isolates of polypores fungi with high laccase activity and data on the inducer effect in the batik waste degradation by selected isolate. Batik waste is potential pollution to the environment. It has been found that the Polyporaceae fungus reduce water pollution caused by batik waste. Fungal fruiting bodies were collected at the Cibinong Science Center and forest park IPB Campus Darmaga, Bogor. The inducers used included 15 g/L sucrose, 200 μM CuSO4, and 1.5% sorghum waste. Seven isolates of polypores fungi were obtained. Isolate J6 with high laccase activity was obtained and identified as Coriolopsis sp. The addition of sorghum waste to the growth medium increased the laccase activity of Coriolopsis sp. J6 by 1428 U/mL. Coriolopsis sp. J6 was able to reduce the color of Poly R-478 by 83.73% after the addition of sucrose and incubation for 10 days. This fungus was able to reduce the color of batik waste by 37.17% after the addition of 1.5% sorghum waste and incubation for 10 days.

Environmental and molecular approach to dye industry waste degradation by the ascomycete fungus Nectriella pironii

Textile industry effluents and landfill leachate contain chemicals such as dyes, heavy metals and aromatic amines characterized by their mutagenicity, cytotoxicity and carcinogenicity. The aim of the present study was investigation of the ascomycete fungus N. pironii isolated from urban postindustrial textile green space for its ability to grow and retain metabolic activity in the presence of the dye industry waste. Research focused mainly on dyes, heavy metals and aromatic amines, which had been detected in landfill leachate via HPLC–MS/MS analysis. Presence of all tested compounds as well as leachate in the growth medium clearly favored the growth of fungal biomass. Only slight growth limitation was observed in the presence of 50 mg L-1o-tolidine. The fungus eliminated o-tolidine as well as dyes at all tested concentrations. The presence of metals slightly influenced the decolorization of the azo dyes; however, it was still similar to 90%. During fungal growth, o-tolidine was hydroxylated and/or converted to toluidine and its derivatives. Laccase and cytochrome P450 involvement in this process has been revealed. The results presented in the paper provide a valuable background for the development of a fungus-based system for the elimination of toxic pollutants generated by the textile industry.

The microbial metabolic activity on carbohydrates and polymers impact the biodegradability of landfilled solid waste

Biological waste degradation is the main driving factor for landfill emissions. In a 2-year laboratory experiment simulating different landfill in-situ aeration scenarios, the microbial degradation of solid waste under different oxygen conditions (treatments) was investigated. Nine landfill simulation reactors were operated in triplicates under three distinct treatments. Three were kept anaerobic, three were aerated for 706 days after an initial anaerobic phase and three were aerated for 244 days in between two anaerobic phases. In total, 36 solid and 36 leachate samples were taken. Biolog® EcoPlates™ were used to assess the functional diversity of the microbial community. It was possible to directly relate the functional diversity to the biodegradability of MSW (municipal solid waste), measured as RI4 (respiration index after 4 days). The differences between the treatments in RI4 as well as in carbon and polymer degradation potential were small. Initially, a RI4 of about 6.5 to 8 mg O2 kg−1 DW was reduced to less than 1 mg O2 kg−1 DW within 114 days of treatment. After the termination of aeration, an increase 3 mg O2 kg−1 DW was observed. By calculating the integral of the Gompertz equation based on spline interpolation of the Biolog® EcoPlates™ results after 96 h two substrate groups mainly contributing to the biodegradability were identified: carbohydrates and polymers. The microbial activity of the respective microbial consortium could thus be related to the biodegradability with a multilinear regression model.

A review of anaerobic landfill bioreactor using leachate recirculation to increase methane gas recovery

Municipal Solid Waste (MSW) treatment with anaerobic landfill bioreactor utilizes landfill as a place of biodegradation and produces methane gas which can be used as renewable alternative energy source. Anaerobic landfill bioreactor technology is a landfill development method that can increase waste degradation and increase biogas production. The increase of biogas and the removal of pollutants from leachate needs to pay attention to the factors that influence the success of anaerobic landfill bioreactor, including pH value, temperature, water content, and COD concentration after recirculation, and methane production. The relationship between these factors was discussed in depth in this paper. The method used is a narrative review where metadata is obtained from Google Scholar and Web of Science. This study explains the development of an anaerobic landfill bioreactor and conducts a synthesis for future research development plans by leachate recirculation.

Isolation and screening of local cellulolytic fungi from the digestive tract larvae of Oryctes rhinoceros L., North Sumatra

Cellulose, which is the main component of plant cell walls from higher plants, has been studied from different aspects. It is insoluble in a wide variety of solvents and is resistant to various chemicals treatments. Fungi are a group of cellulose-degrading microbes and plays major role in recycling of lignocellulosic material in nature. This study aimed to obtain cellulolytic fungi from the digestive tract of Oryctes rhinoceros L. larvae and to determine cellulolytic activity. Isolation and screening of cellulolytic fungi in the digestive tract of insects were carried out with specific medium Carboxymethyl Cellulose (CMC) and the Congo Red method to obtain potential cellulolytic isolates. Eleven fungal isolates showed positive results as cellulolytic fungi. The highest cellulolytic activity was obtained from isolate F05L with a cellulolytic index of 0.90 and isolate F10L of 0.66. The smallest cellulolytic activity was obtained from isolate F02L with a cellulolytic index of 0.14. All isolates would be identified to the species level and analyzed its potential applications. Our result can provide in addition to the environmental and industrial fields, cellulolytic fungi can a solution to the problem of pollution, namely reducing the amount of cellulose waste, and can be added value to the use of waste into processed organic fertilizers to be able to provide solutions to the problem of organic waste degradation.

Optimization of organic waste processing using Black Soldier Fly larvae Case study: Diponegoro university

Waste that is not handled correctly can cause problems for humans and the environment. Therefore, proper waste management efforts are needed to solve this waste problem. One method of processing organic waste is the use of Black Soldier Fly (BSF) larvae. Larvae BSF can degrade organic waste, and the life cycle of BSF acts as a decomposer. This study examines BSF larvae’s ability to decompose biodegradable organic waste, especially for banana waste, cucumber waste, and food waste in the Diponegoro University environment, and to decide the effect of the variable type of food. The frequency of feeding carried out on the growth rate of BSF larvae and to choose the decomposition results of biodegradable organic waste carried out by BSF larvae. This research method is carried out by comparing the effectiveness of waste degradation by BFS with EM4. The value of significance in degrading waste is obtained from the calculation of the Waste Reduction Index, or it can be called WRI. The analysis results show that the WRI value in waste processing using BFS is more significant than in waste processing using EM4. That concludes that BSF fly larvae (Hermetia illucens) effectively reduce organic waste compared to EM4.

Applying PICRUSt and 16S rRNA functional characterisation to predicting co-digestion strategies of various animal manures for biogas production

An estimated 25 million tons of animal manure is produced globally every year, causing considerable impact to the environment. These impacts can be managed through the use of anaerobic digestion (AD) This process achieves waste degradation through enzymatic activity, the efficiency of the AD process is directly related to microorganisms that produce these enzymes. Biomethane potential (BMP) assays remain the standard theoretical framework to pre-determine biogas yield and have been used to determine the feasibility of substrates or their combination for biogas production. However, an integrated approach that combines substrate choice and co-digestion would provide an improvement to the current predictive models. PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) addresses the limitations of assays in this regard. In this paper, the biochemical functions of horse, cow, and pig manures are predicted. A total of 135 predicted KEGG Orthologies (KOs) showed amino acids, carbohydrate, energy, lipid, and xenobiotic metabolisms in all the samples. Linear discriminant analysis (LDA) combined with the effect size measurements (LEfSe), showed that fructose, mannose, amino acid and nucleotide sugar, phosphotransferase (PST) as well as starch and sucrose metabolisms were significantly higher in horse manure samples. 36 of the KOs were related to the acidogenesis and/or acetogenesis AD stages. Extended bar plots showed that 11 significant predictions were observed for horse-cow, while 5 were predicted for horse-pig and for cow-pig manures. Based on these predictions, the AD process can be enhanced through co-digestion strategies that takes into account the predicted metabolic contributions of the manure samples. The results supported the BMP calculations for the samples in this study. Biogas yields can be improved if this combined approach is employed in routine analysis before co-digesting different substrates.