Estimation of growth in solid state fermentation: A review

@#Carleysmith and Fox (1984) stated “without doubt, the single most vital yet most problematical value sought duringfermentation is biomass estimation”. Achieving a positive result in determining biomass remains a major challenge insolid state fermentation (SSF). Fungi are well-characterised microorganisms and are widely used in SSF due to theirability to colonise and penetrate into the solid substrate. The compressed structure of the mycelia and the solid substratedoes not allow a complete recovery of the biomass, which may not be insurmountable. Since the use of a directtechnique such as the dry weight method is impractical, the use of an indirect estimation technique is the only alternative.This review examines strategies that have been used to estimate biomass in SSF. Many promising indirect estimationtechniques are available, which can be classified into six categories as follows; (i) measuring cell components notpresent in the substrate; (ii) measuring biomass component present in both substrate and biomass; (iii) measuring othersecondary metabolites; (iv) measuring metabolic activity; (v) measuring images from direct microscopic observation and(vi) measuring biomass from the substrate matrix. New potential technique and future directions are also discussed inthis review. Although significant advances have been made with the availability of various techniques; however, progresshas been very unsatisfactory. The evaluation of microbial growth in SSF may sometimes become laborious, impracticaland inaccurate. Essentially, this remains another critical issue for monitoring growth. The information of the profile offungal biomass growth throughout any SSF process constitutes an essential parameter in estimation of kinetic variablesand subsequently, scale-up of the process.

Extracted substrate colour as an indicator of fungal growth in solid state fermentation

Aims: In solid state fermentation (SSF), estimation of biomass is difficult as fungal mycelium penetrates deep and remains attached to the solid substrate particles. This study examines and evaluates a new technique based on colour changes of fermented substrates during SSF as an indicator for fungal growth. Methodology and Results: SSF refers to microbial fermentation, which takes place in the absence or near absence of free water, thus being close to the natural environment in which the selected microorganisms, especially fungi, are naturally adapted. Although many promising methods are available, the evaluation of microbial growth in SSF may sometimes become difficult, impractical, and inaccurate. Essentially, this remains another critical issue for monitoring growth. In this study, measurements of colour changes of fermented substrates during SSF are used as indicators for growth and this technique has a potential to be used to quantify growth of microbes. For the growth of Aspergillus awamori and A. oryzae on wheat bran, soybean hulls, and rapeseed meal, it was confirmed that colour changes were directly proportional to the fungal growth. This new approach is an important complementation to the existing techniques, especially for basic studies. The advantages of this method are its ease of use, fast, non-destructive, cheap, and requires no special and expensive reagents. The key finding is that the colorimetric technique demonstrated in this study provides good means to estimate growth than that obtained by visual observation or spores counting.

Allometry of the babassu palm growing on a slash-and-burn agroecosystem of the eastern periphery of Amazonia / Allometria da palmeira babaçu em um agroecossistema de derruba-e-queima na periferia este da Amazônia

Babassu (Attalea speciosa C.Martius, Arecaceae) is a palm with extraordinary socioeconomic and ecologic importance in large areas of tropical Brazil, especially in frequently burned and degraded landscapes. Nevertheless, surprisingly little is known about this keystone species. This paper investigates the allometry of babassu, in order to improve understanding on palm architecture and to provide researchers with an efficient tool for aboveground biomass estimation of juvenile and adult palms. Juvenile leaf biomass can be accurately predicted with the easily measurable minimum diameter of rachis at 30 cm extension. Adult palm biomass can be estimated based on woody stem height, a variable fairly easily measurable on-field. Leaf biomass of adult palms was highly variable, averaged 31.7 percent of aboveground biomass and can be estimated only indirectly through the relationships between wood:leaf-ratio and total aboveground biomass. Carbon contents varied little in the babassu palm, without size- or growth-stage related differences, suggesting the general applicability of values (42.5 percent C for stems, 39.8 percent C for leaves). As a consequence of the limited secondary diameter growth inherent to palms, stem diameter of adult palms is unrelated to palm height and biomass. Stem tapering decreases with increasing palm height. This is partially compensated by increasing wood density in near cylindrical stems. Nevertheless, maximum babassu palm height of about 30 meters appears to be dictated by mechanical stability constraints. All allometric relationships of babassu described in this study are not affected by vegetation stand age, indicating the general applicability of these relationships.

A palmeira babaçu (Attalea speciosa C.Martius, Arecaceae) tem grande importância socioeconômica e ecológica em grande parte da área tropical brasileira, especialmente em áreas degradadas por queimadas freqüentes na Amazônia. No entanto, ainda pouco se sabe sobre as características ecológicas desta espécie-chave. Este estudo investiga a alometria do babaçu com o objetivo de estabelecer uma metodologia eficiente na estimativa da biomassa aérea de palmeiras juvenis e adultas e para um melhor entendimento da sua arquitetura. A biomassa de palmeiras juvenis pode ser estimada facilmente e com precisão com o diâmetro mínimo das ráquis das folhas a 30 cm de extensão. A biomassa de palmeiras adultas pode ser estimada com base na altura do tronco lenhoso, também relativamente de fácil medição em campo. A biomassa foliar das palmeiras adultas foi em media 31,7 por cento da biomassa aérea, porém houve uma alta variação e, portanto, somente pode ser estimada indiretamente através da relação entre a razão madeira:folha e biomassa aérea total. Os teores de carbono no babaçu apresentaram baixa variação, sem diferenças sistemáticas em relação ao tamanho ou estágio de crescimento, o que aponta à aplicabilidade geral dos valores 42.5 por cento C para troncos, 39.8 por cento C para folhas. Em conseqüência do limitado crescimento secundário do diâmetro inerente de palmeiras, não houve relação do diâmetro de tronco com a altura e a biomassa das palmeiras adultas. Observou-se que o afilamento do caule diminui com o aumento da altura das palmeiras, o que é parcialmente compensado pelo incremento da densidade de madeira em troncos quase-cilíndricos. No entanto, a altura máxima do babaçu, de cerca de 30 metros, aparentemente está definida por limitações na estabilidade mecânica. Todas as relações alométricas aqui descritas são independentes da idade da vegetação, indicando a aplicabilidade geral das relações encontradas.

Allometric models for estimating the phytomass of a secondary Atlantic Forest area of southeastern Brazil / Modelos alométricos para estimativa de fitomassa de Floresta Atlântica secundária no sudeste do Brasil

The purpose of this study was to develop and validate equations to estimate the aboveground phytomass of a 30 years old plot of Atlantic Forest. In two plots of 100 m², a total of 82 trees were cut down at ground level. For each tree, height and diameter were measured. Leaves and woody material were separated in order to determine their fresh weights in field conditions. Samples of each fraction were oven dried at 80 ºC to constant weight to determine their dry weight. Tree data were divided into two random samples. One sample was used for the development of the regression equations, and the other for validation. The models were developed using single linear regression analysis, where the dependent variable was the dry mass, and the independent variables were height (h), diameter (d) and d²h. The validation was carried out using Pearson correlation coefficient, paired t-Student test and standard error of estimation. The best equations to estimate aboveground phytomass were: lnDW = -3.068+2.522lnd (r² = 0.91; s y/x = 0.67) and lnDW = -3.676+0.951ln d²h (r² = 0.94; s y/x = 0.56).

O objetivo deste estudo foi desenvolver e validar modelos preditores para a fitomassa epigéa de uma área de Floresta Atlântica secundária. Em duas parcelas de 100m², 82 árvores foram cortadas, ao nível do solo, e anotadas suas medidas de altura e diâmetro. As folhas foram separadas dos ramos para determinação do massa fresca da porção foliar e lenhosa. Amostras de cada fração foram secas em estufa a 80 ºC, até massa constante, para determinação do massa seca. As árvores foram distribuídas em duas amostras aleatórias, sendo uma utilizada para o desenvolvimento das equações de regressão, e a outra para validá-las. Os modelos foram desenvolvidos através da análise de regressão linear simples, tendo como variável dependente a massa seca (DW) e, como variáveis independentes a altura (h), o diâmetro (d) e o quadrado do diâmetro multiplicado pela altura (d²h). A validação foi analisada através da comparação entre os valores obtidos em campo e os estimados pelas equações, através da análise de correlação intraclasse de Pearson e teste t-Sudent pareado. As melhores equações para estimar o massa seca das árvores foram: lnDW = -3,068+2,522lnd (r² = 0,91; s y/x = 0,67) e lnDW = -3,676+0,951ln d²h (r² = 0,94; s y/x = 0,56).

Close relationship between diameters at 30cm height and at breast height (DBH)

This paper proposes the establishment of a second diameter measuring standard at 30cm shoot extension ('diam30') as input variable for allometric biomass estimation of small and mid-sized plant shoots. This diameter standard is better suited than the diameter at breast height (DBH, i.e. diameter at 1.30m shoot extension) for adequate characterization of plant dimensions in low bushy vegetation or in primary forest undergrowth. The relationships between both diameter standards are established based on a dataset of 8645 tree, liana and palm shoots in secondary and primary forests of central Amazonia (ranging from 1-150mm dbh). Dbh can be predicted from the diam(30) with high precision, the error introduced by diameter transformation is only 2-3 percent for trees and palms, and 5 percent for lianas. This is well acceptable for most field study purposes. Relationships deviate slightly from linearity and differ between growth forms. Relationships were markedly similar for different vegetation types (low secondary regrowth vs. primary forests), soils, and selected genera or species. This points to a general validity and applicability of diameter transformations for other field studies. This study provides researchers with a tool for the allometric estimation of biomass in low or structurally heterogeneous vegetation. Rather than applying a uniform diameter standard, the measuring position which best represents the respective plant can be decided on shoot-by-shoot. Plant diameters measured at 30cm height can be transformed to dbh for subsequent allometric biomass estimation. We recommend the use of these diameter transformations only for plants extending well beyond the theoretical minimum shoot length (i.e., >2m height). This study also prepares the ground for the comparability and compatability of future allometric equations specifically developed for small- to mid-sized vegetation components (i.e., bushes, undergrowth) which are based on...

Este estudo propõe o estabelecimento de um segundo padrão de medição de diâmetro a 30 cm de extensão do tronco ('diam30') para a estimativa alométrica da biomassa de plantas de pequeno até médio porte. Considera-se este padrão de diâmetro mais adequado do que o diâmetro à altura do peito ('DAP', a 1,30m de extensão do tronco) para a caracterização das dimensões de plantas em vegetação baixa ou no sub-bosque da mata primária. O presente trabalho investiga as relações entre os dois padrões de diâmetro, baseado em 8645 troncos de árvores, cipós e palmeiras arbóreas (com diâmetros entre 1 e 150mm DAP) em capoeiras e mata primária da Amazônia Central. Conclui-se que se pode estimar o DAP do diam30 com alta precisão, o erro causado pela transformação dos diâmetros é somente 2-3 por cento para árvores e palmeiras e 5 por cento para os cipós, níveis bem aceitáveis para a maioria dos estudos de campo. As relações entre os diâmetros desviaram levemente da linearidade e são diferentes para os três hábitos de crescimento. No entanto, as equações são bastante similares entre os diferentes tipos de vegetação (capoeira baixa vs. mata primária), solos e gêneros ou espécies, indicando sua aplicabilidade e validade geral para outros estudos de campo. Esse trabalho fornece ao pesquisador de campo uma ferramenta para a estimativa alométrica da biomassa de vegetação baixa ou estruturalmente heterogênea. Em vez de utilizar um único padrão uniforme de diâmetro pode-se escolher livremente e individualmente qual posição de diâmetro melhor representa cada tronco. Os diâmetros a 30 cm de extensão do tronco podem ser transformados para o dap para uma subseqüente estimação alométrica da sua biomassa. Recomenda-se o uso destas transformações de diâmetros somente acima de uma extensão mínima do tronco (>2m de altura). Os resultados do presente trabalho também preparam a base para a comparabilidade e compatibilidade de futuras equações alométricas baseadas no diam(30)...