Isolation of Cellulolytic Microfungi Involved in Wood-Waste Decomposition: Prospects for Enzymatic Hydrolysis of Cellulosic Wastes

Wood-wastes from dump-sites at Okobaba Saw-mills on the western part of the Lagos lagoon were examined for cellulolytic microorganisms. Cellulolytic microfungi were isolated from the wastes using minimal salt agar medium containing 0.2% (w/v) crystalline cellulose, sugarcane pulp, corn cob or saw-dust as sole carbon/energy source. The colonies of cellulolytic microfungi which appeared on the plates increased in size and number as the incubation period (days) increased. Among the fungal isolates were two pathogenic Aspergilli (A flavus and A fumigatus), three different black Aspergilli (herein designated as A.niger I, A.niger II and A.niger III), Botrytis cinerea, Fusarium species and Penicillium species. Cell-free filtrates of 7 – day cultures of A.flavus, A.niger I, A.niger II, B. cinerea and P.species grown on the minimal salt broth supplemented with crystalline cellulose as sole carbon/energy source showed very significant CM–cellulase activity. P. species gave a very high value that was over 4 times the value for the closest organism, A.niger II. There is a good propect for cellulase production using the virgin strain of P. species isolated from the wood-wastes

Potentials of cellulosic wastes in media formulation

Potential use of cellulosic wastes as carbon and energy sources in selective media formulations was investigated. Two agar media, Czapek-Dox and Sabouraud’s agar, were modified by substituting their carbon sources with cellulose, sawdust and sugarcane pulps. Then, two fungi; Aspergillus niger ANL301 and Penicillium chrysogenum PCL501, newly isolated from wood-wastes, were transferred to the unmodified and modified media and their growth was monitored for 120 h. Growth of the organisms on modified media containing sawdust and sugarcane pulp compared favorably with that obtained for the unmodified equivalents. Modified Czapek-Dox agar containing 2% (w/v) sawdust (Wood agar) and sugarcane pulps (Cane agar) gave 78.9 – 93.3% of the maximum growth obtained on Sabouraud’s agar. The modified Sabouraud’s agar containing sawdust (Wood-Pep agar) and sugarcane pulps (Cane-Pep agar) yielded 84.4 – 100% of the maximum growth on Sabouraud’s agar. Cellulose-containing media gave a lower level of growth (60.0 – 66.7%) of that obtained for the unmodified media

CELLULASE PRODUCTION BY WILD STRAINS OF ASPERGILLUS NIGER, PENICILLIUM CHRYSOGENUM AND TRICHODERMA HARZIANUM GROWN ON WASTE CELLULOSIC MATERIALS.

Waste cellulosic materials (corncob, sawdust and sugarcane pulp) and crystalline cellulose induced cellulase production in wild strains of Aspergillus niger, Penicillium chrysogenum and Trichoderma harzianum isolated from a wood-waste dump in Lagos, Nigeria. Cellulose-supplemented media gave the maximum cellulase activity of -1 0.54, 0.67 and 0.39 units mg Protein for A. niger, P. chrysogenum and T. harzianum respectively. The maximum enzyme activity for A. niger was obtained at 36 hours of cultivation, while P. chrysogenum and T. harzianum gave their optimal enzyme activities at 12 and 60 hours respectively. Of the three cellulosic wastes, best enzyme -1 activity was obtained with sawdust. Maximum enzyme activity of 0.30, 0.24 and 0.20 units mg Protein respectively was obtained with A. niger, P. chrysogenum and T. harzianum at 144 hours of cultivation using the substrate. A. niger gave the highest enzyme activity with any of the three cellulosic materials followed by P. chrysogenum. It thus appears that the use of sawdust presents the best option for low-cost commercial production of cellulase using A. niger and P. chrysogenum as discussed herewit

Effect of carbon sources on cellulase (EC 3. 2. 1. 4) production by Penicillium chrysogenum PCL501

The effects of glucose, crystalline cellulose and sawdust of Mitragyna cilata on the growth and cellulase production, inferred from cellulase (EC 3. 2. 1. 4) activity, of Penicillium chrysogenum PCL501 was determined. Glucose-containing media gave the highest mycelia weight of 1.78 mg mL-1 in 120 h of incubation. This is about 3.5 – 4.5 times the maximum weights of 0.51 and 0.40 mg mL-1 respectively obtained from the cultures containing cellulose and sawdust. The cultures containing crystalline cellulose and sawdust produced extracellular protein with cellulase (EC 3. 2. 1. 4) activity whereas glucose-containing cultures yielded very low protein and no significant cellulase activity. Maximum protein content of 0.02, 0.13 and 0.46 mg mL-1 respectively were obtained from the cultures containing glucose, cellulose and sawdust. Peak cellulase activity values of 100.0 and 92.2 Units L-1 respectively were obtained for the cultures containing cellulose and sawdust. There is a correlation between the protein released and cellulase activity of the culture filtrates. P. chrysogenum PCL501 produces extracellular proteins with significant cellulase activity in media containing cellulose and sawdust but not in glucose-containing medium. Sawdust is indicated as a good inducer of cellulase activity in the organism. The waste cellulosic material can be used as low-cost carbon source for commercial cellulase production

Potentials of cellulosic wastes in media formulation

Potential use of cellulosic wastes as carbon and energy sources in selective media formulations was investigated. Two agar media, Czapek-Dox and Sabouraud’s agar, were modified by substituting theircarbon sources with cellulose, sawdust and sugarcane pulps. Then, two fungi; Aspergillus niger ANL301 and Penicillium chrysogenum PCL501, newly isolated from wood-wastes, were transferred to the unmodified and modified media and their growth was monitored for 120 h. Growth of the organisms on modified media containing sawdust and sugarcane pulp compared favorably with that obtained for the unmodified equivalents. Modified Czapek-Dox agar containing 2% (w/v) sawdust (Wood agar) and sugarcane pulps (Cane agar) gave 78.9 – 93.3% of the maximum growth obtained on Sabouraud’s agar. The modified Sabouraud’s agar containing sawdust (Wood-Pep agar) and sugarcane pulps (Cane-Pep agar) yielded 84.4 – 100% of the maximum growth on Sabouraud’s agar. Cellulose-containing media gave a lower level of growth (60.0 – 66.7%) of that obtained for the unmodified media

Pectinolytic activity of wild-type filamentous fungi fermented on agro-wastes

Five filamentous fungi (Aspergillus clavatus, Aspergillus niger, Fusarium sp., Penicillum chrysogenum and Trichoderma sp.) isolated from agrowaste samples in Lagos metropolis, Nigeria, depolymerized citrus pectin. Best pectolytic activity, as indicated by the diameter of clear, hydrolyzed zones on the medium plates containing commercial citrus pectin as sole carbon source, was obtained with A. niger, closely followed by P. chrysogenum. The two fungi also produced pectinases with different agrowastes (pineapple peel, orange peels, sawdust, sugarcane pulps and wheat bran) as the sole carbon source. The highest pectinase activity by both fungi was produce with wheat bran as the sole carbon source. Peak pectinase activity of 350.28 ± 2.82 and 478.25 ± 3.04 IU mg-1 protein was respectively obtained by submerged fermentation (SmF) at 48 h for A. niger and P.chrysogenum in media containing wheat bran as the sole carbon source. Solid-state fermentation (SSF) yielded higher levels of pectinase activity than the SmF. The strains of A. niger and P. chrysogenum have good prospect for pectinase production. Wheat bran is a good low-cost fermentation substrate for pectinase production by the investigated fungi

EVALUATION OF THE PROXIMATE, MINERAL AND VITAMIN COMPOSITIONS OF ACALYPHA WILKESIANA LEAF

Acalypha wilkesiana, commonly known as “Copper leaf” and belonging to the Euphorbiaceae family, is a tropical shrub renowned for its ornamental beauty and diverse cultural uses. Its leaves are frequently utilized by locals for various medicinal purposes. This study evaluated the proximate, mineral and vitamin compositions of Acalypha wilkesiana leaf. Proximate analysis was conducted using standard methods, while the mineral concentrations were determined by means of atomic absorption spectrophotometer, and vitamins were quantified using appropriate colorimetric and titration methods. The percentage proximate composition for moisture, ash, fiber, protein, fat, and carbohydrates were 13.75±1.75, 12.75±0.75, 8.00±0.60, 3.65±0.05, 12.90±0.10, and 48.95±0.45, respectively, while the energy value was 326±1.10 kcal/g. The mineral analysis revealed that the leaf is rich in sodium, potassium, phosphorus, magnesium, manganese, calcium and zinc, with concentrations (mg/g) of 3.96±0.05, 2.89±1.79, 2.73±0.25, 1.94±0.08, 1.40±1.01, 1.31±0.42 and 0.30±0.14, respectively. The fat soluble vitamins ranged from 4.12±0.26 (for vitamin D) ¬¬to 17.28±1.00 mg/kg (for vitamin E), while the water soluble vitamins ranged from 0.05±0.02 mg/100g (for vitamin B2) to 69.61±1.77 mg/kg (for vitamin C). The results show that Acalypha wilkesiana leaf is a good source of nutrients, minerals and vitamins, and could serve as a dietary supplement for addressing nutritional deficiencies

A Novel Unsupervised Method to Identify Genes Important in the Anti-viral Response: Application to Interferon/Ribavirin in Hepatitis C Patients

Background: Treating hepatitis C with interferon/ribavirin results in a varied response in terms of decrease in viral titer and ultimate outcome. Marked responders have a sharp decline in viral titer within a few days of treatment initiation, whereas in other patients there is no effect on the virus (poor responders). Previous studies have shown that combination therapy modifies expression of hundreds of genes in vitro and in vivo. However, identifying which, if any, of these genes have a role in viral clearance remains challenging. Aims: The goal of this paper is to link viral levels with gene expression and thereby identify genes that may be responsible for early decrease in viral titer. Methods: Microarrays were performed on RNA isolated from PBMC of patients undergoing interferon/ribavirin therapy. Samples were collected at pre-treatment (day 0), and 1, 2, 7, 14 and 28 days after initiating treatment. A novel method was applied to identify genes that are linked to a decrease in viral titer during interferon/ribavirin treatment. The method uses the relationship between inter-patient gene expression based proximities and inter-patient viral titer based proximities to define the association between microarray gene expression measurements of each gene and viral-titer measurements. Results: We detected 36 unique genes whose expressions provide a clustering of patients that resembles viral titer based clustering of patients. These genes include IRF7, MX1, OASL and OAS2, viperin and many ISG's of unknown function. Conclusion: The genes identified by this method appear to play a major role in the reduction of hepatitis C virus during the early phase of treatment. The method has broad utility and can be used to analyze response to any group of factors influencing biological outcome such as antiviral drugs or anti-cancer agents where microarray data are available. © 2007 Brodsky et al

Synthetic biology and biomass conversion: a match made in heaven?

To move our economy onto a sustainable basis, it is essential that we find a replacement for fossil carbon as a source of liquid fuels and chemical industry feedstocks. Lignocellulosic biomass, available in enormous quantities, is the only feasible replacement. Many micro-organisms are capable of rapid and efficient degradation of biomass, employing a battery of specialized enzymes, but do not produce useful products. Attempts to transfer biomass-degrading capability to industrially useful organisms by heterologous expression of one or a few biomass-degrading enzymes have met with limited success. It seems probable that an effective biomass-degradation system requires the synergistic action of a large number of enzymes, the individual and collective actions of which are poorly understood. By offering the ability to combine any number of transgenes in a modular, combinatorial way, synthetic biology offers a new approach to elucidating the synergistic action of combinations of biomass-degrading enzymes in vivo and may ultimately lead to a transferable biomass-degradation system. Also, synthetic biology offers the potential for assembly of novel product-formation pathways, as well as mechanisms for increased solvent tolerance. Thus, synthetic biology may finally lead to cheap and effective processes for conversion of biomass to useful products