• Energy Research
• Bioresource Technology close
• Netherlands close

Penicillium subrubescens is able to degrade a broad range of plant biomass and it has an expanded set of Carbohydrate Active enzyme (CAZyme)-encoding genes in comparison to other Penicillium species. Here we used exoproteome and transcriptome analysis to demonstrate the versatile plant biomass degradation mechanism by P. subrubescens during growth on wheat bran and sugar beet pulp. On wheat bran P. subrubescens degraded xylan main chain and side residues from Day 2 of cultivation, whereas it started to degrade side chains of pectin in sugar beet pulp prior to attacking the main chain on Day 3. In addition, on Day 3 the cellulolytic enzymes were highly increased. Our results confirm that P. subrubescens adapts its enzyme production to the available plant biomass and is a promising new fungal cell factory for the production of CAZymes.

With a view to boost practical implementation of lignin conversion technologies, this paper assesses the availability of industrial lignin and evaluates pricing strategies applicable to multi-product biorefineries. The biorefineries, producing either denatured ethanol or sugar hydrolysate as a main product, can yield 43% and 61% of lignin residue (LR) comprising 33% and 23% of lignin by mass, respectively, without sacrificing the output of the main product and before electricity import has become indispensable. Analysis of the pricing strategies reveals that LR must be treated as a low-value by-product, and its minimum selling price (MSP) is driven mainly by the prevailing electricity price. Under the biorefinery net zero energy balance, and taking into account the LR market price adequacy, as well as the main probabilistic conditions, the upper range for the MSP is calculated at $43-70 and $18-37 per ton for biorefineries producing ethanol and hydrolysate, respectively.

The effects of thermochemical treatments (aquathermolysis, pyrolysis, and combinations thereof) on the lignocellulosic structure and composition of wheat straw were studied with (13)C and (1)H solid state NMR spectroscopy and proton T1ρ relaxation measurements. Results show that aquathermolysis removes hemicellulose, acetyl groups, and ash minerals. As a result, the susceptibility of lignocellulose to pyrolysis is reduced most likely due to the removal of catalytically active salts, although recondensation of lignin during aquathermolysis treatment can also play a role. In contrast to pyrolysis of wheat straw, pyrolysis of aquathermolysed wheat straw leaves traces of cellulose in the char as well as more intense lignin methoxy peaks. Finally, it was found that both pyrolysis chars contain aliphatic chains, which were attributed to the presence of cutin or cutin-like materials, a macromolecule that covers the aerial surface of plants, not soluble in water and seemingly stable under the pyrolysis conditions applied.

The interest in biomass as a source of renewable energy and chemicals has been increasing in keeping up with the transition to a sustainable bio-based economy. An important initial step of chemicals recovery from biomass-derived pyrolysis oil is water extraction where most of polar compounds are isolated in the aqueous phase. This study was done to investigate the effects of stirring rate and water-to-oil ratio on the extraction capability (distribution coefficient and yield), water content, and atomic composition of both aqueous and organic phases. The results show that the stirring rate above 300 rpm has no influence on the equilibrium. Increasing the water-to-oil ratio dilutes the aqueous phase without changing the atomic distribution. Forest residue-derived pyrolysis oil should be extracted at a water-to-oil ratio of 0.65-0.7, whereas pine-derived pyrolysis oil is preferably extracted at the lowest feasible water-to-oil ratio where complete phase separation occurs, which is 0.5 in this study.

La gazéification au plasma de la biomasse ligneuse, non ligneuse et algale brute et torréfiée à l'aide de trois agents de gazéification différents (air, vapeur et CO2) est effectuée par une analyse thermodynamique. Les impacts de la matière première et de l'atmosphère de réaction sur divers indices de performance tels que le rendement du gaz de synthèse, les émissions de polluants, le rapport énergie plasmatique/production de gaz de synthèse (PSR) et l'efficacité de la gazéification du plasma (PGE) sont étudiés. Les résultats montrent que la gazéification au plasma de CO2 donne le PSR le plus bas, conduisant ainsi à la PGE la plus élevée parmi les trois atmosphères réactionnelles. La biomasse torréfiée présente un rendement accru en gaz de synthèse et en PGE, mais est plus susceptible d'avoir un impact environnemental négatif des polluants N/S par rapport à la biomasse brute, en particulier pour la paille de riz. Cependant, l'exception concerne le marc de raisin torréfié et les macroalgues qui produisent des quantités plus faibles d'espèces S dans des atmosphères de vapeur et de CO2. Dans l'ensemble, le bois de pin torréfié présente les meilleures performances pour la production de gaz de synthèse de haute qualité contenant de faibles impuretés parmi les matières premières étudiées. La gasificación por plasma de biomasa leñosa cruda y torrefactada, no leñosa y de algas utilizando tres agentes gasificantes diferentes (aire, vapor y CO2) se realiza a través de un análisis termodinámico. Se estudian los impactos de la materia prima y la atmósfera de reacción en varios índices de rendimiento, como el rendimiento de gas de síntesis, las emisiones contaminantes, la relación de producción de energía de plasma a gas de síntesis (PSR) y la eficiencia de gasificación de plasma (PGE). Los resultados muestran que la gasificación con plasma de CO2 da el PSR más bajo, lo que conduce al PGE más alto entre las tres atmósferas de reacción. La biomasa torrefactada muestra un mayor rendimiento de gas de síntesis y PGE, pero es más probable que tenga un impacto ambiental negativo de los contaminantes N/S en comparación con los crudos, especialmente para la paja de arroz. Sin embargo, la excepción es para el orujo de uva torrefactado y las macroalgas que producen menores cantidades de especies S en atmósferas de vapor y CO2. En general, la madera de pino torrefactada tiene el mejor rendimiento para producir gas de síntesis de alta calidad que contiene bajas impurezas entre las materias primas investigadas. Plasma gasification of raw and torrefied woody, non-woody, and algal biomass using three different gasifying agents (air, steam, and CO2) is conducted through a thermodynamic analysis. The impacts of feedstock and reaction atmosphere on various performance indices such as syngas yield, pollutant emissions, plasma energy to syngas production ratio (PSR), and plasma gasification efficiency (PGE) are studied. Results show that CO2 plasma gasification gives the lowest PSR, thereby leading to the highest PGE among the three reaction atmospheres. Torrefied biomass displays increased syngas yield and PGE, but is more likely to have a negative environmental impact of N/S pollutants in comparison with raw one, especially for rice straw. However, the exception is for torrefied grape marc and macroalgae which produce lower amounts of S-species under steam and CO2 atmospheres. Overall, torrefied pine wood has the best performance for producing high quality syngas containing low impurities among the investigated feedstocks. يتم تغويز البلازما للكتلة الحيوية الخشبية وغير الخشبية والطحالب باستخدام ثلاثة عوامل تغويز مختلفة (الهواء والبخار وثاني أكسيد الكربون) من خلال تحليل ديناميكي حراري. يتم دراسة تأثيرات المواد الخام وجو التفاعل على مؤشرات الأداء المختلفة مثل إنتاج غاز التخليق وانبعاثات الملوثات وطاقة البلازما على نسبة إنتاج غاز التخليق (PSR) وكفاءة تغويز البلازما (PGE). تظهر النتائج أن تغويز بلازما ثاني أكسيد الكربون يعطي أقل نسبة PSR، مما يؤدي إلى أعلى نسبة PGE بين أجواء التفاعل الثلاثة. تعرض الكتلة الحيوية Torrefied زيادة إنتاج غاز التخليق و PGE، ولكن من المرجح أن يكون لها تأثير بيئي سلبي على ملوثات N/S مقارنة بالملوثات الخام، خاصة بالنسبة لقش الأرز. ومع ذلك، فإن الاستثناء هو لمارك العنب والطحالب الكبيرة التي تنتج كميات أقل من الأنواع S تحت أجواء البخار وثاني أكسيد الكربون. بشكل عام، يتمتع خشب الصنوبر المغطى بأفضل أداء لإنتاج غاز صناعي عالي الجودة يحتوي على شوائب منخفضة بين المواد الأولية التي تم التحقيق فيها.

This study evaluated a novel three-stage process devoted to the cascade production of lactate, biohydrogen and methane from tequila vinasse (TV), with emphasis on attaining a high and stable biohydrogen production rate (HPR) by utilizing lactate as biohydrogen precursor. In the first stage, tailored operating conditions applied to a sequencing batch reactor were effective in sustaining a lactate concentration of 12.4 g/L, corresponding to 89% of the total organic acids produced. In the second stage, the stimulation of lactate-centered dark fermentation which entails the decoupling of biohydrogen production from carbohydrates utilization was an effective approach enabling stable biohydrogen production, having HPR fluctuations less than 10% with a maximum HPR of 12.3 L/L-d and a biohydrogen yield of 3.1 L/LTV. Finally, 1.6 L CH4/L-d and 6.5 L CH4/LTV were obtained when feeding the biohydrogen fermentation effluent to a third methanogenic stage, yielding a global energy recovery of 267.5 kJ/LTV.

Torrefaction is suggested to be an effective method to improve the fuel properties of biomass and gasification of torrefied biomass should provide a higher quality product gas than that from unprocessed biomass. In this study, both raw and torrefied Miscanthus × giganteus (M×G) were gasified in an air-blown bubbling fluidized bed (BFB) gasifier using olivine as the bed material. The effects of equivalence ratio (ER) (0.18-0.32) and bed temperature (660-850°C) on the gasification performance were investigated. The results obtained suggest the optimum gasification conditions for the torrefied M × G are ER 0.21 and 800°C. The product gas from these process conditions had a higher heating value (HHV) of 6.70 MJ/m(3), gas yield 2m(3)/kg biomass (H2 8.6%, CO 16.4% and CH4 4.4%) and cold gas efficiency 62.7%. The comparison between raw and torrefied M × G indicates that the torrefied M × G is more suitable BFB gasification.