Duckweed (Lemna minor) is a novel natural inducer of cellulase production in Trichoderma reesei

Sustainable valorization of macroalgae residual biomass, optimization of pyrolysis parameters and life cycle assessment

The major challenges for the current climate change issue are an increase in global energy demand, a limited supply of fossil fuels, and increasing carbon footprints from fossil fuels, which have necessitated the exploration of sustainable alternatives to fossil fuels. Biorefineries offer a promising path to sustainable fuel production, converting biomass into biofuels using diverse technologies. Aquatic biomass, such as macroalgae in this context, represents an abundant and renewable biomass resource that can be cultivated from water bodies without competing with traditional agricultural land. Despite this, the potential of macroalgae for biofuel production remains largely untapped, with very limited studies addressing their viability and efficiency. This study investigates the efficient conversion of unexplored macroalgae biomass through a biorefinery process that involves lipid extraction to produce biodiesel, along with the production of biochar and bio-oil from the pyrolysis of residual biomass. To improve the effectiveness and overall performance of the pyrolysis system, Response Surface Methodology (RSM) was utilized through a Box-Behnken design to systematically investigate how alterations in temperature, reaction time, and catalyst concentration influence the production of bio-oil and biochar to maximize their yields. The results showed the highest bio-oil yield achieved to be 36 %, while the highest biochar yield reached 45 %. The integration of Life Cycle Assessment (LCA) in the study helps to assess carbon emission and environmental burdens and identify potential areas for optimization, such as resource efficiency, waste management, and energy utilization. The LCA results contribute to the identification of potential environmental hotspots and guide the development of strategies to optimize the overall sustainability of the biofuel production process. The LCA results indicate that the solvent (chloroform) used in transesterification contributes significantly to greenhouse gas emissions and climate change impacts. Therefore, it is crucial to explore alternative, safe solvents that can mitigate the environmental impacts of transesterification.

Cellulase and chitinase activities and antagonism against Fusarium oxysporum f.sp. cubense race 1 of six Trichoderma strains isolated from Mexican maize cropping

OBJECTIVE

To evaluate the enzymatic and biocontrol capacity of native Trichoderma strains isolated from corn crops in Irapuato (state of Guanajuato) and Napízaro (state of Michoacán), Mexico.

RESULTS

Six native strains from Irapuato and Napízaro were tested, with five of them identified as T. harzianum and one as T. tomentosum. The six strains qualitatively and quantitatively showed enzyme activity for cellulase and chitinase. The best results were obtained for strains IrV6SIC7 and MichV6S2C2 with 878 IU L^-1 of chitinase and 1323 IU L^-1 of cellulase, respectively. All Trichoderma strains acted antagonistically toward Fusarium oxysporum f.sp. cubense race 1 (FocR1), with percentages of inhibition that ranged from 9 to 54%. In addition, the microscopic analysis allowed visualizing the mechanisms of mycoparasitism and antibiosis by either IrV6SIC7 or MichV6S2C2. The latter effects indicate that the tested native Trichoderma strains isolated from corn crops possessed enzymatic mechanisms as a strategy for biocontrolling FocR1 strains.

CONCLUSION

The enzyme production by the Trichoderma strains represents a potential biotechnological utilization for either agricultural or industrial purposes.

Production of poly (l-lactide)-degrading enzyme by Actinomadura keratinilytica strain T16-1 under solid state fermentation using agricultural wastes as substrate

Poly (l-lactide) (PLLA) is an aliphatic polyester that can be obtained from renewable resources and degraded by various microorganisms. In previous reports, Actinomadura keratinilytica strain T16-1 demonstrated high ability to degrade PLLA under various conditions. PLLA-degrading enzyme production under solid state fermentation has been sparsely studied. PLLA-degrading enzyme production by A. keratinilytica strain T16-1 was investigated using agricultural wastes as substrate under solid state fermentation (SSF). Three agricultural wastes as soybean meal, cassava chips and duckweed were tested as substrates for PLLA-degrading enzyme production by statistical methods using mixture design. Results revealed that using duckweed as the substrate gave the highest enzyme production (138.66 ± 13.57 U/g dry substrate). Maximum enzyme activity of 391.24 ± 15.57 U/g dry substrate was obtained under 10 g duckweed, 10% inoculum size, 7 days of cultivation time, pH 7.0, 2.8% PLLA powder, and 60% moisture content at 45 °C. It can be concluded that duckweed is an inexpensive substrate, which reduces the costs of PLLA-degrading enzyme production, as an alternative to effective water weed management.

Current perspective on production and applications of microbial cellulases: a review

The potential of cellulolytic enzymes has been widely studied and explored for bioconversion processes and plays a key role in various industrial applications. Cellulase, a key enzyme for cellulose-rich waste feedstock-based biorefinery, has increasing demand in various industries, e.g., paper and pulp, juice clarification, etc. Also, there has been constant progress in developing new strategies to enhance its production, such as the application of waste feedstock as the substrate for the production of individual or enzyme cocktails, process parameters control, and genetic manipulations for enzyme production with enhanced yield, efficiency, and specificity. Further, an insight into immobilization techniques has also been presented for improved reusability of cellulase, a critical factor that controls the cost of the enzyme at an industrial scale. In addition, the review also gives an insight into the status of the significant application of cellulase in the industrial sector, with its techno-economic analysis for future applications. The present review gives a complete overview of current perspectives on the production of microbial cellulases as a promising tool to develop a sustainable and greener concept for industrial applications.

Single and Binary Equilibrium Studies for Ni2+ and Zn2+ Biosorption onto Lemna gibba from Aqueous Solutions

The biosorption ability of Lemna gibba for removing Ni2+ and Zn2+ ions in aqueous batch systems, both individually and simultaneously, was examined. The influences of solution pH and initial single and binary metal concentrations on equilibrium Ni2+ and Zn2+ biosorption was explored. The optimal solution pH for Ni2+ and Zn2+ biosorption was 6.0, for both the single and binary metal systems. Ni2+ and Zn2+ biosorption capacities increased with increasing initial metal concentrations. The presence of Zn2+ ions more adversely affected the biosorption of Ni2+ ions in the binary metal systems than vice versa. The single and binary biosorption isotherms of Ni2+ and Zn2+ revealed that L. gibba’s affinity for Zn2+ ions was higher than that for Ni2+ ions. The Redlich–Peterson and Freundlich isotherm models fit well to the experimental equilibrium data of Ni2+ ions, whereas Redlich–Peterson and Langmuir models better described the equilibrium data of Zn2+ ions in single metal systems. The modified Sips isotherm model best fit the competitive biosorption data of Ni2+-Zn2+ on L. gibba. FTIR analyses suggest the involvement of hemicellulose and cellulose in the biosorption of Ni2+ and Zn2+. The presence of Ni2+ and Zn2+ on the L.gibba surface was validated by SEM-EDX.